Revert of Caching the result of readPixelsSupported (https://codereview.chromium.org/364193004/)

Reason for revert:
appears to crash GM on Ubuntu and Win8

http://108.170.220.120:10117/builders/Test-Ubuntu12-ShuttleA-GTX660-x86-Release/builds/1237/steps/GenerateGMs/logs/stdio

Original issue's description:
> Caching the result of readPixelsSupported
>
> The call was calling GR_GL_GetIntegerv 2 times for each readPixels
> and thus was causing a loss of performance
>
> (resubmit of issue 344793008)
>
> Benchmark url: http://packages.gkny.fr/tst/index.html
>
> BUG=skia:2681
>
> Committed: https://skia.googlesource.com/skia/+/753a2964afe5661ce9b2a8ca77ca9d0aabd3173c

R=junov@chromium.org, piotaixr@chromium.org
TBR=junov@chromium.org, piotaixr@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=skia:2681

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/367323003

3 files changed, 9 insertions, 82 deletions

diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 2e85eb5adc..8f2d4c1297 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -504,7 +504,7 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     // First check version for support
     if (kGL_GrGLStandard == standard) {
         hasETC1 = hasCompressTex2D &&
-            (version >= GR_GL_VER(4, 3) ||
+            (version >= GR_GL_VER(4, 3) || 
              ctxInfo.hasExtension("GL_ARB_ES3_compatibility"));
     } else {
         hasETC1 = hasCompressTex2D &&
@@ -560,7 +560,7 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     }
 }
 
-bool GrGLCaps::doReadPixelsSupported(const GrGLInterface* intf,
+bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
                                    GrGLenum format,
                                    GrGLenum type) const {
     if (GR_GL_RGBA == format && GR_GL_UNSIGNED_BYTE == type) {
@@ -589,25 +589,6 @@ bool GrGLCaps::doReadPixelsSupported(const GrGLInterface* intf,
     return (GrGLenum)otherFormat == format && (GrGLenum)otherType == type;
 }
 
-bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
-                                   GrGLenum format,
-                                   GrGLenum type,
-                                   GrGLenum currFboFormat) const {
-
-    ReadPixelsSupportedFormatsKey key = {format, type, currFboFormat};
-
-    ReadPixelsSupportedFormats* cachedValue = fReadPixelsSupportedCache.find(key);
-
-    if (cachedValue == NULL) {
-        bool value = doReadPixelsSupported(intf, format, type);
-        cachedValue = new ReadPixelsSupportedFormats(key, value);
-
-        fReadPixelsSupportedCache.add(cachedValue);
-    }
-
-    return cachedValue->value();
-}
-
 void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     fMSFBOType = kNone_MSFBOType;
@@ -836,17 +817,3 @@ SkString GrGLCaps::dump() const {
     r.appendf("Drops tile on zero divide: %s\n", (fDropsTileOnZeroDivide ? "YES" : "NO"));
     return r;
 }
-
-//Computes a hash based on the three values in the key struct
-// bits 31------------15---------7---------------0
-//      fFormat(15:0) fType(7:0) fFboFormat(7:0)
-uint32_t GrGLCaps::ReadPixelsSupportedFormats::Hash(const ReadPixelsSupportedFormatsKey& key) {
-    // fFormat has different values like 0x190X or 0x8XXX: 16 bits are required
-    uint32_t hash = ((key.fFormat & 0xFFFF) << 16);
-    // fType is 0x14XX: 8 lower bits are enough
-    hash |= ((key.fType & 0xFF) << 8);
-    // fFboFormat is enum GrPixelConfig which has less than 15 values: 8 bits OK
-    hash |= (key.fFboFormat & 0xFF);
-
-    return hash;
-}
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 24bf83afbb..ccf04fd7ba 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -13,7 +13,6 @@
 #include "GrGLStencilBuffer.h"
 #include "SkTArray.h"
 #include "SkTDArray.h"
-#include "SkTDynamicHash.h"
 
 class GrGLContextInfo;
 
@@ -254,8 +253,7 @@ public:
     /// Does ReadPixels support the provided format/type combo?
     bool readPixelsSupported(const GrGLInterface* intf,
                              GrGLenum format,
-                             GrGLenum type,
-                             GrGLenum currFboFormat) const;
+                             GrGLenum type) const;
 
     bool isCoreProfile() const { return fIsCoreProfile; }
 
@@ -326,10 +324,6 @@ private:
     void initConfigRenderableTable(const GrGLContextInfo&);
     void initConfigTexturableTable(const GrGLContextInfo&, const GrGLInterface*);
 
-    bool doReadPixelsSupported(const GrGLInterface* intf,
-                                   GrGLenum format,
-                                   GrGLenum type) const;
-
     // tracks configs that have been verified to pass the FBO completeness when
     // used as a color attachment
     VerifiedColorConfigs fVerifiedColorConfigs;
@@ -370,38 +364,6 @@ private:
     bool fFullClearIsFree : 1;
     bool fDropsTileOnZeroDivide : 1;
 
-    struct ReadPixelsSupportedFormatsKey {
-        GrGLenum fFormat;
-        GrGLenum fType;
-        GrGLenum fFboFormat;
-
-        bool operator==(const ReadPixelsSupportedFormatsKey& rhs) const {
-            return fFormat == rhs.fFormat
-                    && fType == rhs.fType
-                    && fFboFormat == rhs.fFboFormat;
-        }
-    };
-
-    class ReadPixelsSupportedFormats {
-    public:
-        ReadPixelsSupportedFormats(ReadPixelsSupportedFormatsKey key,
-                                   bool value)
-            :fKey(key), fValue(value) {
-        }
-
-        static const ReadPixelsSupportedFormatsKey& GetKey(const ReadPixelsSupportedFormats& element) {
-            return element.fKey;
-        }
-        static uint32_t Hash(const ReadPixelsSupportedFormatsKey&);
-
-        bool value() const { return fValue; }
-    private:
-        ReadPixelsSupportedFormatsKey fKey;
-        bool fValue;
-    };
-
-    mutable SkTDynamicHash<ReadPixelsSupportedFormats, ReadPixelsSupportedFormatsKey> fReadPixelsSupportedCache;
-
     typedef GrDrawTargetCaps INHERITED;
 };
 
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index 73938b8374..2eb76a5aff 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -170,6 +170,8 @@ GrGpuGL::~GrGpuGL() {
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+
+
 GrPixelConfig GrGpuGL::preferredReadPixelsConfig(GrPixelConfig readConfig,
                                                  GrPixelConfig surfaceConfig) const {
     if (GR_GL_RGBA_8888_PIXEL_OPS_SLOW && kRGBA_8888_GrPixelConfig == readConfig) {
@@ -180,13 +182,9 @@ GrPixelConfig GrGpuGL::preferredReadPixelsConfig(GrPixelConfig readConfig,
         // Mesa 3D takes a slow path on when reading back  BGRA from an RGBA surface and vice-versa.
         // Perhaps this should be guarded by some compiletime or runtime check.
         return surfaceConfig;
-    } else if (readConfig == kBGRA_8888_GrPixelConfig
-            && this->glCaps().readPixelsSupported(
-                this->glInterface(),
-                GR_GL_BGRA,
-                GR_GL_UNSIGNED_BYTE,
-                fHWBoundRenderTarget->config()
-            )) {
+    } else if (readConfig == kBGRA_8888_GrPixelConfig &&
+               !this->glCaps().readPixelsSupported(this->glInterface(),
+                                                   GR_GL_BGRA, GR_GL_UNSIGNED_BYTE)) {
         return kRGBA_8888_GrPixelConfig;
     } else {
         return readConfig;
@@ -715,7 +713,7 @@ bool GrGpuGL::uploadTexData(const GrGLTexture::Desc& desc,
 }
 
 // TODO: This function is using a lot of wonky semantics like, if width == -1
-// then set width = desc.fWdith ... blah. A better way to do it might be to
+// then set width = desc.fWdith ... blah. A better way to do it might be to 
 // create a CompressedTexData struct that takes a desc/ptr and figures out
 // the proper upload semantics. Then users can construct this function how they
 // see fit if they want to go against the "standard" way to do it.