Modify Blink.Canvas.toDataURL UMA performance metrics

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

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
index 099ed9080c084be9c1987ce7a1e9d5a4746a0cb6..2ac47d8003ccd5f03b40459fab5f713c63bfc992 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
@@ -699,6 +699,30 @@ String HTMLCanvasElement::toDataURLInternal(
 
   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
@@ -722,61 +746,6 @@ String HTMLCanvasElement::toDataURL(const String& mimeType,
     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()) {