Modify Blink.Canvas.toDataURL UMA performance metrics

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 681 matching lines @@
 
 String HTMLCanvasElement::toDataURLInternal(
     const String& mimeType,
     const double& quality,
     SourceDrawingBuffer sourceBuffer) const {
   if (!isPaintable())
     return String("data:,");
 
   String encodingMimeType = toEncodingMimeType(mimeType, EncodeReasonToDataURL);
 
+  Optional<ScopedUsHistogramTimer> timer;
+  if (encodingMimeType == "image/png") {
+    DEFINE_THREAD_SAFE_STATIC_LOCAL(
+        CustomCountHistogram, scopedUsCounterPNG,
+        new CustomCountHistogram("Blink.Canvas.ToDataURL.PNG", 0, 10000000,
+                                 50));
+    timer.emplace(scopedUsCounterPNG);
+  } else if (encodingMimeType == "image/jpeg") {
+    DEFINE_THREAD_SAFE_STATIC_LOCAL(
+        CustomCountHistogram, scopedUsCounterJPEG,
+        new CustomCountHistogram("Blink.Canvas.ToDataURL.JPEG", 0, 10000000,
+                                 50));
+    timer.emplace(scopedUsCounterJPEG);
+  } else if (encodingMimeType == "image/webp") {
+    DEFINE_THREAD_SAFE_STATIC_LOCAL(
+        CustomCountHistogram, scopedUsCounterWEBP,
+        new CustomCountHistogram("Blink.Canvas.ToDataURL.WEBP", 0, 10000000,
+                                 50));
+    timer.emplace(scopedUsCounterWEBP);
+  } else {
+    // Currently we only support three encoding types.
+    NOTREACHED();
+  }
+
   ImageData* imageData = toImageData(sourceBuffer, SnapshotReasonToDataURL);
 
   if (!imageData)  // allocation failure
     return String("data:,");
 
   return ImageDataBuffer(imageData->size(), imageData->data()->data())
       .toDataURL(encodingMimeType, quality);
 }
 
 String HTMLCanvasElement::toDataURL(const String& mimeType,
                                     const ScriptValue& qualityArgument,
                                     ExceptionState& exceptionState) const {
   if (surfaceLayerBridge()) {
     exceptionState.throwDOMException(InvalidStateError,
                                      "canvas.toDataURL is not allowed for a "
                                      "canvas that has transferred its control "
                                      "to offscreen.");
     return String();
   }
   if (!originClean()) {
     exceptionState.throwSecurityError("Tainted canvases may not be exported.");
     return String();
   }
-  Optional<ScopedUsHistogramTimer> timer;
-  String lowercaseMimeType = mimeType.lower();
-  if (mimeType.isNull())
-    lowercaseMimeType = DefaultMimeType;
-  if (lowercaseMimeType == "image/png") {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterPNG,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.PNG", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterPNG);
-  } else if (lowercaseMimeType == "image/jpeg") {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterJPEG,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.JPEG", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterJPEG);
-  } else if (lowercaseMimeType == "image/webp") {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterWEBP,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.WEBP", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterWEBP);
-  } else if (lowercaseMimeType == "image/gif") {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterGIF,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.GIF", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterGIF);
-  } else if (lowercaseMimeType == "image/bmp" ||
-             lowercaseMimeType == "image/x-windows-bmp") {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterBMP,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.BMP", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterBMP);
-  } else if (lowercaseMimeType == "image/x-icon") {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterICON,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.ICON", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterICON);
-  } else if (lowercaseMimeType == "image/tiff" ||
-             lowercaseMimeType == "image/x-tiff") {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterTIFF,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.TIFF", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterTIFF);
-  } else {
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(
-        CustomCountHistogram, scopedUsCounterUnknown,
-        new CustomCountHistogram("Blink.Canvas.ToDataURL.Unknown", 0, 10000000,
-                                 50));
-    timer.emplace(scopedUsCounterUnknown);
-  }
 
   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);
 }
@@ skipping 649 matching lines @@
   mojom::blink::OffscreenCanvasSurfacePtr service;
   Platform::current()->interfaceProvider()->getInterface(
       mojo::GetProxy(&service));
   m_surfaceLayerBridge =
       wrapUnique(new CanvasSurfaceLayerBridge(std::move(service)));
   return m_surfaceLayerBridge->createSurfaceLayer(this->width(),
                                                   this->height());
 }
 
 }  // namespace blink