cc: Add image decode control in the compositor.

This patch reworks ImageDecodeController and the surrounding
system to give control over image decodes to the compositor.

Perf note:

This is disabled on android, and should only affect desktop.
That being said, this patch changes the behavior with
respect to image decodes, so some perf changes are expected.

BUG=516751
R=enne, reed1
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1418573002

Cr-Commit-Position: refs/heads/master@{#370188}

1 files changed, 15 insertions, 0 deletions

diff --git a/cc/playback/discardable_image_map.h b/cc/playback/discardable_image_map.h
index f0535c1..1244c6c 100644
--- a/cc/playback/discardable_image_map.h
+++ b/cc/playback/discardable_image_map.h
@@ -20,6 +20,21 @@ class SkImage;
 
 namespace cc {
 
+// Helper function to apply the matrix to the rect and return the result.
+SkRect MapRect(const SkMatrix& matrix, const SkRect& src);
+
+// Helper funciton to extract a scale from the matrix. Returns true on success
+// and false on failure.
+bool ExtractScale(const SkMatrix& matrix, SkSize* scale);
+
+// Helper function to compute the new rect bounds adjusted for both the current
+// paint and all of the saved paints. Returns true on success and false on
+// failure.
+bool ComputeRectBoundsFromPaint(const SkRect& rect,
+                                const SkPaint* current_paint,
+                                const std::vector<const SkPaint*>& saved_paints,
+                                SkRect* paint_bounds);
+
 // This class is used for generating discardable images data (see DrawImage
 // for the type of data it stores). It allows the client to query a particular
 // rect and get back a list of DrawImages in that rect.