Remove full-size bitmap copy on SkImage::scalePixels->IFG::decodeAndScale

third_party/WebKit/Source/platform/graphics/ImageFrameGeneratorTest.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 122 matching lines @@
 
   char buffer[100 * 100 * 4];
   m_generator->decodeAndScale(m_segmentReader.get(), false, 0, imageInfo(),
                               buffer, 100 * 4);
   EXPECT_EQ(1, m_decodeRequestCount);
 
   addNewData();
   m_generator->decodeAndScale(m_segmentReader.get(), false, 0, imageInfo(),
                               buffer, 100 * 4);
   EXPECT_EQ(2, m_decodeRequestCount);
+
   EXPECT_EQ(0, m_decodersDestroyed);
 }
 
 TEST_F(ImageFrameGeneratorTest, incompleteDecodeBecomesComplete) {
   setFrameStatus(ImageFrame::FramePartial);
 
   char buffer[100 * 100 * 4];
   m_generator->decodeAndScale(m_segmentReader.get(), false, 0, imageInfo(),
                               buffer, 100 * 4);
   EXPECT_EQ(1, m_decodeRequestCount);
   EXPECT_EQ(0, m_decodersDestroyed);
 
   setFrameStatus(ImageFrame::FrameComplete);
   addNewData();
 
   m_generator->decodeAndScale(m_segmentReader.get(), false, 0, imageInfo(),
                               buffer, 100 * 4);
   EXPECT_EQ(2, m_decodeRequestCount);
   EXPECT_EQ(1, m_decodersDestroyed);
 
   // Decoder created again.
   m_generator->decodeAndScale(m_segmentReader.get(), false, 0, imageInfo(),
                               buffer, 100 * 4);
   EXPECT_EQ(3, m_decodeRequestCount);
 }
 
+TEST_F(ImageFrameGeneratorTest, scaleAfterDecode) {
+  setFrameStatus(ImageFrame::FramePartial);
+
+  char scaledBuffer[30 * 30 * 4];
+  m_generator->decodeAndScale(m_segmentReader.get(), false, 0,
+                              imageInfo().makeWH(30, 30), scaledBuffer, 30 * 4);
+  EXPECT_EQ(1, m_decodeRequestCount);
+
+  char buffer[100 * 100 * 4];
+  addNewData();
+  m_generator->decodeAndScale(m_segmentReader.get(), false, 0, imageInfo(),
+                              buffer, 100 * 4);
+  EXPECT_EQ(2, m_decodeRequestCount);
+
+  char scaledBuffer1[45 * 48 * 4];
+  addNewData();
+  m_generator->decodeAndScale(m_segmentReader.get(), false, 0,
+                              imageInfo().makeWH(45, 45), scaledBuffer1,
+                              48 * 4);
+  EXPECT_EQ(3, m_decodeRequestCount);
+  EXPECT_EQ(0, m_decodersDestroyed);
+
+  setFrameStatus(ImageFrame::FrameComplete);
+  addNewData();
+
+  m_generator->decodeAndScale(m_segmentReader.get(), false, 0,
+                              imageInfo().makeWH(30, 30), scaledBuffer, 30 * 4);
+  EXPECT_EQ(4, m_decodeRequestCount);
+  EXPECT_EQ(1, m_decodersDestroyed);
+}
+
 static void decodeThreadMain(ImageFrameGenerator* generator,
                              SegmentReader* segmentReader) {
   char buffer[100 * 100 * 4];
   generator->decodeAndScale(segmentReader, false, 0, imageInfo(), buffer,
                             100 * 4);
 }
 
 TEST_F(ImageFrameGeneratorTest, incompleteDecodeBecomesCompleteMultiThreaded) {
   setFrameStatus(ImageFrame::FramePartial);
 
@@ skipping 75 matching lines @@
   // all the frame data, but not destroying the decoder.  See comments in
   // ImageFrameGenerator::tryToResumeDecode().
   m_generator->decodeAndScale(m_segmentReader.get(), true, 2, imageInfo(),
                               buffer, 100 * 4);
   EXPECT_EQ(3, m_decodeRequestCount);
   EXPECT_EQ(0, m_decodersDestroyed);
   EXPECT_EQ(kNotFound, m_requestedClearExceptFrame);
 }
 
 }  // namespace blink