Reland "Avoid drawing BW clipped color glyphs many times."

This reverts commit 8a95244f626c2f7d4b66c8ca18266c2b0640bebb.

Reason for revert: Didn't actually break anything.

Original change's description:
> Revert "Avoid drawing BW clipped color glyphs many times."
> 
> This reverts commit bba38ee80e4140908ac0c351dc18a2f1224e5f0a.
> 
> Reason for revert: possibly breaking chrome text
> 
> Original change's description:
> > Avoid drawing BW clipped color glyphs many times.
> > 
> > Prior to this change if a color glyph is drawn through the raster device
> > with an aliased clip the glyph is drawn once for each rectangular region
> > in the aliased clip. In addition, even when the glyph was not a color
> > glyph in this situation, the mask was checked for being a color glyph
> > once for each rectangular region of the aliased clip. This change hoists
> > the test for the color format out of the loop to ensure that the mask
> > format is checked once and the mask is drawn once.
> > 
> > This issue was discovered by rotating the coloremoji_blendmodes gm.
> > 
> > Change-Id: I18b6b546356780e0b00948fff7b65783219f5c92
> > Reviewed-on: https://skia-review.googlesource.com/125868
> > Reviewed-by: Mike Reed <reed@google.com>
> > Commit-Queue: Ben Wagner <bungeman@google.com>
> 
> TBR=mtklein@google.com,bungeman@google.com,reed@google.com
> 
> # Not skipping CQ checks because original CL landed > 1 day ago.
> 
> Change-Id: Ife6d7255f9cb88b6f9d7a3c5800e88cc065e475b
> Reviewed-on: https://skia-review.googlesource.com/126401
> Reviewed-by: Greg Daniel <egdaniel@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,mtklein@google.com,bungeman@google.com,reed@google.com

Change-Id: I7fc4c1f901bcee482f6b118b192caee14c112e43
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/126540
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>

1 files changed, 21 insertions, 16 deletions

diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index 0526f76f8e..34f5da5cfe 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -1441,11 +1441,15 @@ public:
             SkRegion::Cliperator clipper(*fClip, mask.fBounds);
 
             if (!clipper.done() && this->getImageData(glyph, &mask)) {
-                const SkIRect& cr = clipper.rect();
-                do {
-                    this->blitMask(mask, cr);
-                    clipper.next();
-                } while (!clipper.done());
+                if (SkMask::kARGB32_Format == mask.fFormat) {
+                    this->blitARGB32Mask(mask);
+                } else {
+                    const SkIRect& cr = clipper.rect();
+                    do {
+                        fBlitter->blitMask(mask, cr);
+                        clipper.next();
+                    } while (!clipper.done());
+                }
             }
         } else {
             SkIRect  storage;
@@ -1460,7 +1464,11 @@ public:
             }
 
             if (this->getImageData(glyph, &mask)) {
-                this->blitMask(mask, *bounds);
+                if (SkMask::kARGB32_Format == mask.fFormat) {
+                    this->blitARGB32Mask(mask);
+                } else {
+                    fBlitter->blitMask(mask, *bounds);
+                }
             }
         }
     }
@@ -1491,17 +1499,14 @@ private:
         return true;
     }
 
-    void blitMask(const SkMask& mask, const SkIRect& clip) const {
-        if (SkMask::kARGB32_Format == mask.fFormat) {
-            SkBitmap bm;
-            bm.installPixels(
-                SkImageInfo::MakeN32Premul(mask.fBounds.width(), mask.fBounds.height()),
-                (SkPMColor*)mask.fImage, mask.fRowBytes);
+    void blitARGB32Mask(const SkMask& mask) const {
+        SkASSERT(SkMask::kARGB32_Format == mask.fFormat);
+        SkBitmap bm;
+        bm.installPixels(
+            SkImageInfo::MakeN32Premul(mask.fBounds.width(), mask.fBounds.height()),
+            (SkPMColor*)mask.fImage, mask.fRowBytes);
 
-            fDraw.drawSprite(bm, mask.fBounds.x(), mask.fBounds.y(), fPaint);
-        } else {
-            fBlitter->blitMask(mask, clip);
-        }
+        fDraw.drawSprite(bm, mask.fBounds.x(), mask.fBounds.y(), fPaint);
     }
 
     const bool            fUseRegionToDraw;