Make sure RecordingImageBufferSurface's current frame is valid

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/graphics/RecordingImageBufferSurface.h"
 
 #include "platform/Histogram.h"
 #include "platform/graphics/CanvasMetrics.h"
 #include "platform/graphics/ExpensiveCanvasHeuristicParameters.h"
 #include "platform/graphics/GraphicsContext.h"
@@ skipping 240 matching lines @@
 
 void RecordingImageBufferSurface::didDraw(const FloatRect& rect)
 {
     m_didRecordDrawCommandsInCurrentFrame = true;
     IntRect pixelBounds = enclosingIntRect(rect);
     m_currentFramePixelCount += pixelBounds.width() * pixelBounds.height();
 }
 
 bool RecordingImageBufferSurface::finalizeFrameInternal(FallbackReason* fallbackReason)
 {
     ASSERT(!m_fallbackSurface);

[Justin Novosad, 2016/07/04 14:38:55]

I meant this one.

[xidachen, 2016/07/04 14:43:36]

Done.

-    ASSERT(m_currentFrame);
-    ASSERT(m_currentFrame->getRecordingCanvas());
+    CHECK(m_currentFrame);
+    CHECK(m_currentFrame->getRecordingCanvas());
     ASSERT(fallbackReason);
     ASSERT(*fallbackReason == FallbackReasonUnknown);
 
     if (!m_imageBuffer->isDirty()) {
         if (!m_previousFrame) {
             // Create an initial blank frame
             m_previousFrame = fromSkSp(m_currentFrame->finishRecordingAsPicture());
             initializeCurrentFrame();
         }
+        CHECK(m_currentFrame);
         return m_currentFrame.get();

[Justin Novosad, 2016/07/04 14:38:55]

tautology: just return true here.

[xidachen, 2016/07/04 14:43:36]

Done.

     }
 
     if (!m_frameWasCleared) {
         *fallbackReason = FallbackReasonCanvasNotClearedBetweenFrames;
         return false;
     }
 
     if (m_fallbackFactory && m_currentFrame->getRecordingCanvas()->getSaveCount() > ExpensiveCanvasHeuristicParameters::ExpensiveRecordingStackDepth) {
         *fallbackReason = FallbackReasonRunawayStateStack;
         return false;
@@ skipping 75 matching lines @@
 
 void RecordingImageBufferSurface::setIsHidden(bool hidden)
 {
     if (m_fallbackSurface)
         m_fallbackSurface->setIsHidden(hidden);
     else
         ImageBufferSurface::setIsHidden(hidden);
 }
 
 } // namespace blink