Adding performance tracking for canvas API calls

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 586 matching lines @@
 
     String encodingMimeType = toEncodingMimeType(mimeType, EncodeReasonToDataURL);
 
     ImageData* imageData = toImageData(sourceBuffer, SnapshotReasonToDataURL);
 
     return ImageDataBuffer(imageData->size(), imageData->data()->data()).toDataURL(encodingMimeType, quality);
 }
 
 String HTMLCanvasElement::toDataURL(const String& mimeType, const ScriptValue& qualityArgument, ExceptionState& exceptionState) const
 {
+    Optional<ScopedUsHistogramTimer> timer;
+    if (m_imageBuffer && m_imageBuffer->isAccelerated()) {
+        DEFINE_STATIC_LOCAL(CustomCountHistogram, scopedUsCounterGPU, ("Blink.Canvas.ToDataURL.GPU", 0, 10000000, 50));

[Justin Novosad, 2016/05/19 15:28:40]

You are missing entries in histograms.xml

+        timer.emplace(scopedUsCounterGPU);
+    } else if (m_imageBuffer && m_imageBuffer->isRecording()) {
+        DEFINE_STATIC_LOCAL(CustomCountHistogram, scopedUsCounterDL, ("Blink.Canvas.ToDataURL.DL", 0, 10000000, 50));

[Justin Novosad, 2016/05/19 15:28:39]

DL -> DisplayList

[xidachen, 2016/05/20 12:36:54]

Changed in all places.

+        timer.emplace(scopedUsCounterDL);
+    } else {
+        DEFINE_STATIC_LOCAL(CustomCountHistogram, scopedUsCounterSW, ("Blink.Canvas.ToDataURL.SW", 0, 10000000, 50));

[Justin Novosad, 2016/05/19 15:28:40]

SW -> CPU

[xidachen, 2016/05/20 12:36:54]

Changed in all places.

+        timer.emplace(scopedUsCounterSW);
+    }
+
     if (!originClean()) {
         exceptionState.throwSecurityError("Tainted canvases may not be exported.");

[Justin Novosad, 2016/05/19 15:36:55]

We should start the measurement after this early exit condition

[xidachen, 2016/05/20 12:36:54]

Done.

         return String();
     }
     double quality = UndefinedQualityValue;
     if (!qualityArgument.isEmpty()) {
         v8::Local<v8::Value> v8Value = qualityArgument.v8Value();
         if (v8Value->IsNumber()) {
             quality = v8Value.As<v8::Number>()->Value();
         }
     }
     return toDataURLInternal(mimeType, quality, BackBuffer);

[Justin Novosad, 2016/05/19 15:36:55]

Specifically for toDataURL, it would make more sense to classify by mimeType
rather than by rendering mode (GPU/CPU/DisplayList).

[xidachen, 2016/05/20 12:36:54]

Done.

 }
 
 void HTMLCanvasElement::toBlob(BlobCallback* callback, const String& mimeType, const ScriptValue& qualityArgument, ExceptionState& exceptionState)
 {
     if (!originClean()) {
         exceptionState.throwSecurityError("Tainted canvases may not be exported.");
         return;
     }
 
     if (!isPaintable()) {
@@ skipping 497 matching lines @@
 }
 
 String HTMLCanvasElement::getIdFromControl(const Element* element)
 {
     if (m_context)
         return m_context->getIdFromControl(element);
     return String();
 }
 
 } // namespace blink