From 052d65cc1411a8c466efa17034c8f15a39401665 Mon Sep 17 00:00:00 2001
From: Jason Simmons <jsimmons@chromium.org>
Date: Mon, 1 Feb 2016 10:33:23 -0800
Subject: [PATCH] Clear the Flow raster cache when a GrContext is destroyed

After an application is suspended and the GrContext associated with the
Flutter view is destroyed, the raster cache still contains images tied
to the defunct context.  The SkyShell process will crash if these images
are used after the application resumes.
---
 flow/paint_context.cc                     | 4 ++++
 flow/paint_context.h                      | 2 ++
 flow/raster_cache.cc                      | 4 ++++
 flow/raster_cache.h                       | 2 ++
 sky/shell/gpu/direct/rasterizer_direct.cc | 1 +
 5 files changed, 13 insertions(+)

diff --git a/flow/paint_context.cc b/flow/paint_context.cc
index ffa4b7c5f..0cc2e9923 100644
--- a/flow/paint_context.cc
+++ b/flow/paint_context.cc
@@ -49,4 +49,8 @@ PaintContext::ScopedFrame::~ScopedFrame() {
 PaintContext::~PaintContext() {
 }
 
+void PaintContext::OnGrContextDestroyed() {
+  raster_cache_.Clear();
+}
+
 }  // namespace flow
diff --git a/flow/paint_context.h b/flow/paint_context.h
index e0fb8fade..3177050d2 100644
--- a/flow/paint_context.h
+++ b/flow/paint_context.h
@@ -51,6 +51,8 @@ class PaintContext {
                            SkCanvas& canvas,
                            bool instrumentation_enabled = true);
 
+  void OnGrContextDestroyed();
+
   RasterCache& raster_cache() { return raster_cache_; }
   const instrumentation::Counter& frame_count() const { return frame_count_; }
   const instrumentation::Stopwatch& frame_time() const { return frame_time_; }
diff --git a/flow/raster_cache.cc b/flow/raster_cache.cc
index 4a2b71f34..0e1f7da0e 100644
--- a/flow/raster_cache.cc
+++ b/flow/raster_cache.cc
@@ -112,4 +112,8 @@ void RasterCache::SweepAfterFrame() {
     cache_.erase(it);
 }
 
+void RasterCache::Clear() {
+  cache_.clear();
+}
+
 }  // namespace flow
diff --git a/flow/raster_cache.h b/flow/raster_cache.h
index 884794f98..633339f12 100644
--- a/flow/raster_cache.h
+++ b/flow/raster_cache.h
@@ -25,6 +25,8 @@ class RasterCache {
       GrContext* context, SkPicture* picture, const SkMatrix& ctm);
   void SweepAfterFrame();
 
+  void Clear();
+
  private:
   struct Entry {
     Entry();
diff --git a/sky/shell/gpu/direct/rasterizer_direct.cc b/sky/shell/gpu/direct/rasterizer_direct.cc
index 2ab63b9f9..40438db88 100644
--- a/sky/shell/gpu/direct/rasterizer_direct.cc
+++ b/sky/shell/gpu/direct/rasterizer_direct.cc
@@ -130,6 +130,7 @@ void RasterizerDirect::Draw(uint64_t layer_tree_ptr,
 void RasterizerDirect::OnOutputSurfaceDestroyed() {
   if (context_) {
     CHECK(context_->MakeCurrent(surface_.get()));
+    paint_context_.OnGrContextDestroyed();
     ganesh_canvas_.SetGrGLInterface(nullptr);
     context_ = nullptr;
   }