Track performance of toBlob and its complete timeout delay

third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreator.h

 // Copyright 2015 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 "core/CoreExport.h"
 #include "core/dom/DOMTypedArray.h"
 #include "core/fileapi/BlobCallback.h"
 #include "platform/geometry/IntSize.h"
 #include "platform/heap/Handle.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/Vector.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class PNGImageEncoderState;
 class JPEGImageEncoderState;
 
 class CORE_EXPORT CanvasAsyncBlobCreator : public GarbageCollectedFinalized<CanvasAsyncBlobCreator> {
 public:
-    static CanvasAsyncBlobCreator* create(DOMUint8ClampedArray* unpremultipliedRGBAImageData, const String& mimeType, const IntSize&, BlobCallback*);
+    static CanvasAsyncBlobCreator* create(DOMUint8ClampedArray* unpremultipliedRGBAImageData, const String& mimeType, const IntSize&, BlobCallback*, double);
     void scheduleAsyncBlobCreation(bool canUseIdlePeriodScheduling, const double& quality = 0.0);
     virtual ~CanvasAsyncBlobCreator();
     enum MimeType {
         MimeTypePng,
         MimeTypeJpeg,
         MimeTypeWebp,
         NumberOfMimeTypeSupported
     };
     enum IdleTaskStatus {
         IdleTaskNotStarted,
         IdleTaskStarted,
         IdleTaskCompleted,
         IdleTaskFailed,
         IdleTaskSwitchedToMainThreadTask,
         IdleTaskNotSupported // Idle tasks are not implemented for some image types
     };
+    // enum used histogram
+    enum IdleTaskTimeoutType {

[Justin Novosad, 2016/06/07 21:43:44]

I find these enum names a bit hard to interpret. We have basically four
categories of outcome: Failed, completed before idle task timeout, completed
after idle task timeout, completed without using idle scheduling (for webp).
each call to toBlob should add a count to exactly one of these bins.  "Failed"
could be expanded into more bins if we want to identify failure types.

+        IdleTaskStartTimeout,
+        IdleTaskCompleteTimeout,
+        IdleTaskTimeoutSupported
+    };
     // Methods are virtual for mocking in unit tests
     virtual void signalTaskSwitchInStartTimeoutEventForTesting() { }
     virtual void signalTaskSwitchInCompleteTimeoutEventForTesting() { }
 
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
         visitor->trace(m_data);
     }
 
 protected:
-    CanvasAsyncBlobCreator(DOMUint8ClampedArray* data, MimeType, const IntSize&, BlobCallback*);
+    CanvasAsyncBlobCreator(DOMUint8ClampedArray* data, MimeType, const IntSize&, BlobCallback*, double);
     // Methods are virtual for unit testing
     virtual void scheduleInitiatePngEncoding();
     virtual void scheduleInitiateJpegEncoding(const double&);
     virtual void idleEncodeRowsPng(double deadlineSeconds);
     virtual void idleEncodeRowsJpeg(double deadlineSeconds);
     virtual void postDelayedTaskToMainThread(const WebTraceLocation&, std::unique_ptr<SameThreadClosure>, double delayMs);
     virtual void signalAlternativeCodePathFinishedForTesting() { }
     virtual void createBlobAndInvokeCallback();
     virtual void createNullAndInvokeCallback();
 
     void initiatePngEncoding(double deadlineSeconds);
     void initiateJpegEncoding(const double& quality, double deadlineSeconds);
     IdleTaskStatus m_idleTaskStatus;
 
 private:
     friend class CanvasAsyncBlobCreatorTest;
 
     OwnPtr<PNGImageEncoderState> m_pngEncoderState;
     OwnPtr<JPEGImageEncoderState> m_jpegEncoderState;
     Member<DOMUint8ClampedArray> m_data;
     OwnPtr<Vector<unsigned char>> m_encodedImage;
     int m_numRowsCompleted;
 
     const IntSize m_size;
     size_t m_pixelRowStride;
     const MimeType m_mimeType;
     CrossThreadPersistent<BlobCallback> m_callback;
+    double m_startTime;
+    void recordTimeoutSwitch(IdleTaskTimeoutType);
 
     // PNG
     bool initializePngStruct();
     void encodeRowsPngOnMainThread(); // Similar to idleEncodeRowsPng without deadline
 
     // JPEG
     bool initializeJpegStruct(double quality);
     void encodeRowsJpegOnMainThread(); // Similar to idleEncodeRowsJpeg without deadline
 
     // WEBP
     void encodeImageOnEncoderThread(double quality);
 
-    void idleTaskStartTimeoutEvent(double quality);
-    void idleTaskCompleteTimeoutEvent();
+    void idleTaskStartTimeoutEvent(double quality, double startTime);
+    void idleTaskCompleteTimeoutEvent(double startTime);
 };
 
 } // namespace blink