Picture Recording: fix the performance bottleneck in SkDeferredCanvas::isFullFrame

blink skips all pending commands during picture recording if it is drawing an opaque full-frame
geometry or image. This may improve performance for some edge cases. To recognize an opaque
full-frame drawing should be cheap enough. Otherwise, the overhead will offset the improvement.
Unfortunately, data from perf for content_shell on Nexus7 shows that SkDeferredCanvas::isFullFrame
is far from cheap. Table below shows that how much isFullFrame() costs in the whole render process.

benchmark                              percentage
my local benchmark(draw 1000 sprites)   4.1%
speedReading                            2.8%
FishIETank(1000 fishes)                 1.5%
GUIMark3 Bitmap                         2.0%

By contrast, real recording (SkGPipeCanvas::drawBitmapRectToRect) and real rasterization
(GrDrawTarget::drawRect) cost ~4% and ~6% in the whole render process respectively. Apparently,
SkDeferredCanvas::isFullFrame() is nontrivial.

getDeviceSize() is the main contributor to this hotspot. The change simply save the canvasSize and
reuse it among drawings if it is not a fresh frame. This change cut off ~65% (or improved ~2 times)
of isFullFrame().

telemetry smoothness canvas_tough_test didn't show obvious improvement or regression.

BUG=411166
R=junov@chromium.org, tomhudson@google.com, reed@google.com

Author: yunchao.he@intel.com

Review URL: https://codereview.chromium.org/545813002

1 files changed, 12 insertions, 1 deletions

diff --git a/src/utils/SkDeferredCanvas.cpp b/src/utils/SkDeferredCanvas.cpp
index b46e92a4a0..cce5dde538 100644
--- a/src/utils/SkDeferredCanvas.cpp
+++ b/src/utils/SkDeferredCanvas.cpp
@@ -526,6 +526,8 @@ SkDeferredCanvas::SkDeferredCanvas(SkDeferredDevice* device) : SkCanvas (device)
 void SkDeferredCanvas::init() {
     fBitmapSizeThreshold = kDeferredCanvasBitmapSizeThreshold;
     fDeferredDrawing = true; // On by default
+    fCachedCanvasSize.setEmpty();
+    fCachedCanvasSizeDirty = true;
 }
 
 void SkDeferredCanvas::setMaxRecordingStorage(size_t maxStorage) {
@@ -589,6 +591,14 @@ bool SkDeferredCanvas::isFreshFrame() const {
     return this->getDeferredDevice()->isFreshFrame();
 }
 
+SkISize SkDeferredCanvas::getCanvasSize() const {
+    if (fCachedCanvasSizeDirty) {
+        fCachedCanvasSize = this->getBaseLayerSize();
+        fCachedCanvasSizeDirty = false;
+    }
+    return fCachedCanvasSize;
+}
+
 bool SkDeferredCanvas::hasPendingCommands() const {
     return this->getDeferredDevice()->hasPendingCommands();
 }
@@ -609,6 +619,7 @@ SkSurface* SkDeferredCanvas::setSurface(SkSurface* surface) {
     // all pending commands, which can help to seamlessly recover from
     // a lost accelerated graphics context.
     deferredDevice->setSurface(surface);
+    fCachedCanvasSizeDirty = true;
     return surface;
 }
 
@@ -632,7 +643,7 @@ SkImage* SkDeferredCanvas::newImageSnapshot() {
 bool SkDeferredCanvas::isFullFrame(const SkRect* rect,
                                    const SkPaint* paint) const {
     SkCanvas* canvas = this->drawingCanvas();
-    SkISize canvasSize = this->getDeviceSize();
+    SkISize canvasSize = this->getCanvasSize();
     if (rect) {
         if (!canvas->getTotalMatrix().rectStaysRect()) {
             return false; // conservative