Revert "remove legacy support for old old picture versions"

This reverts commit f3504d430cec35330017aa2af3a51083801c7dd9.

Reason for revert: breaks unittest in Printing unittest in chrome

Original change's description:
> remove legacy support for old old picture versions
> 
> Bug: skia:
> Change-Id: Ieb97eabdb18e8c7bfa86e6a1fc6e0389cd096daa
> Reviewed-on: https://skia-review.googlesource.com/89860
> Reviewed-by: Florin Malita <fmalita@chromium.org>
> Commit-Queue: Mike Reed <reed@google.com>

TBR=mtklein@google.com,fmalita@chromium.org,reed@google.com

Change-Id: I9f90da5dcfb9543f2f575fa7dc3b9c82996b041d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/90020
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

4 files changed, 35 insertions, 7 deletions

diff --git a/src/core/SkReadBuffer.h b/src/core/SkReadBuffer.h
index 69aaf02ab8..665f4080e3 100644
--- a/src/core/SkReadBuffer.h
+++ b/src/core/SkReadBuffer.h
@@ -68,10 +68,10 @@ public:
         kGradientShaderFloatColor_Version  = 49,
         kXfermodeToBlendMode_Version       = 50,
         kXfermodeToBlendMode2_Version      = 51,
+         */
         kTextBlobImplicitRunCount_Version  = 52,
         kComposeShaderCanLerp_Version      = 54,
         kNoModesInMergeImageFilter_Verison = 55,
-         */
         kTileModeInBlurImageFilter_Version = 56,
         kTileInfoInSweepGradient_Version   = 57,
         k2PtConicalNoFlip_Version          = 58,
diff --git a/src/core/SkTextBlob.cpp b/src/core/SkTextBlob.cpp
index 6d89e6f135..91ec79bcbf 100644
--- a/src/core/SkTextBlob.cpp
+++ b/src/core/SkTextBlob.cpp
@@ -790,13 +790,20 @@ void SkTextBlob::flatten(SkWriteBuffer& buffer) const {
 }
 
 sk_sp<SkTextBlob> SkTextBlob::MakeFromBuffer(SkReadBuffer& reader) {
+    const int runCount = reader.isVersionLT(SkReadBuffer::kTextBlobImplicitRunCount_Version)
+    ? reader.read32() : std::numeric_limits<int>::max();
+    if (runCount < 0) {
+        return nullptr;
+    }
+
     SkRect bounds;
     reader.readRect(&bounds);
 
     SkTextBlobBuilder blobBuilder;
-    for (;;) {
+    for (int i = 0; i < runCount; ++i) {
         int glyphCount = reader.read32();
-        if (glyphCount == 0) {
+        if (glyphCount == 0 &&
+            !reader.isVersionLT(SkReadBuffer::kTextBlobImplicitRunCount_Version)) {
             // End-of-runs marker.
             break;
         }
diff --git a/src/effects/SkMergeImageFilter.cpp b/src/effects/SkMergeImageFilter.cpp
index 1da4d41a0a..1d425ed04e 100644
--- a/src/effects/SkMergeImageFilter.cpp
+++ b/src/effects/SkMergeImageFilter.cpp
@@ -111,10 +111,26 @@ sk_sp<SkImageFilter> SkMergeImageFilter::onMakeColorSpace(SkColorSpaceXformer* x
 
 sk_sp<SkFlattenable> SkMergeImageFilter::CreateProc(SkReadBuffer& buffer) {
     Common common;
-    if (!common.unflatten(buffer, -1) || !buffer.isValid()) {
+    if (!common.unflatten(buffer, -1)) {
         return nullptr;
     }
-    return Make(common.inputs(), common.inputCount(), &common.cropRect());
+
+    const int count = common.inputCount();
+    if (buffer.isVersionLT(SkReadBuffer::kNoModesInMergeImageFilter_Verison)) {
+        bool hasModes = buffer.readBool();
+        if (hasModes) {
+            // Older pictures may have stored blendmodes, but by inspection we think these were
+            // all src-over, so we have removed support for storing these.
+            SkAutoSTArray<4, uint8_t> modes8(count);
+            if (!buffer.readByteArray(modes8.get(), count)) {
+                return nullptr;
+            }
+            if (!buffer.isValid()) {
+                return nullptr;
+            }
+        }
+    }
+    return Make(common.inputs(), count, &common.cropRect());
 }
 
 void SkMergeImageFilter::flatten(SkWriteBuffer& buffer) const {
diff --git a/src/shaders/SkComposeShader.cpp b/src/shaders/SkComposeShader.cpp
index 2feae7788e..34e54863b7 100644
--- a/src/shaders/SkComposeShader.cpp
+++ b/src/shaders/SkComposeShader.cpp
@@ -43,12 +43,17 @@ sk_sp<SkFlattenable> SkComposeShader::CreateProc(SkReadBuffer& buffer) {
     sk_sp<SkShader> dst(buffer.readShader());
     sk_sp<SkShader> src(buffer.readShader());
     unsigned        mode = buffer.read32();
-    float           lerp = buffer.readScalar();
+
+    float lerp = 1;
+    if (!buffer.isVersionLT(SkReadBuffer::kComposeShaderCanLerp_Version)) {
+        lerp = buffer.readScalar();
+    }
 
     // check for valid mode before we cast to the enum type
-    if (!buffer.validate(mode <= (unsigned)SkBlendMode::kLastMode)) {
+    if (mode > (unsigned)SkBlendMode::kLastMode) {
         return nullptr;
     }
+
     return MakeCompose(std::move(dst), std::move(src), static_cast<SkBlendMode>(mode), lerp);
 }