[Android WebView] OnMemoryPressure to drop tile memory

android_webview/browser/in_process_view_renderer.cc

Index: android_webview/browser/in_process_view_renderer.cc
diff --git a/android_webview/browser/in_process_view_renderer.cc b/android_webview/browser/in_process_view_renderer.cc
index 39bd2f6b889b0d7338ee44320991b894ca6dca9e..30e2eedb54ac1484e36866ba354606e38bdcca8e 100644
--- a/android_webview/browser/in_process_view_renderer.cc
+++ b/android_webview/browser/in_process_view_renderer.cc
@@ -316,6 +316,37 @@ bool InProcessViewRenderer::RequestProcessGL() {
   return client_->RequestDrawGL(NULL);
 }
 
+void InProcessViewRenderer::TrimMemory(int level) {

[joth, 2013/10/02 10:47:01]

not using level param? 

ideas:

if level < 10 return

if level > 40 skip over the visibility tests too (line 326) 

[boliu, 2013/10/02 14:09:55]

Not done yet. I'll have to play with this when I get back to my desk.

+  // Nothing to drop.
+  if (!attached_to_window_ || !hardware_initialized_ || !compositor_)
+    return;
+
+  // Do not release resources on view we expect to get DrawGL soon.
+  client_->UpdateGlobalVisibleRect();
+  if (view_visible_ && window_visible_ &&
+      !cached_global_visible_rect_.IsEmpty()) {
+    return;
+  }
+
+  if (!eglGetCurrentContext()) {
+    NOTREACHED();
+    return;
+  }
+
+  TRACE_EVENT0("android_webview", "InProcessViewRenderer::TrimMemory");
+  ScopedAppGLStateRestore state_restore(ScopedAppGLStateRestore::MODE_ON_TRIM);
+  gpu::InProcessCommandBuffer::ProcessGpuWorkOnCurrentThread();
+  ScopedAllowGL allow_gl;
+
+  // Just set the memory limit to 0 and drop all tiles. This will be reset to
+  // normal levels in the next DrawGL call.
+  content::SynchronousCompositorMemoryPolicy policy;
+  policy.bytes_limit = 0;
+  policy.num_resources_limit = 0;
+  compositor_->SetMemoryPolicy(policy);
+  ForceCompositeSW();
+}
+
 void InProcessViewRenderer::UpdateCachedGlobalVisibleRect() {
   client_->UpdateGlobalVisibleRect();
 }
@@ -342,8 +373,9 @@ bool InProcessViewRenderer::InitializeHwDraw() {
   hardware_failed_ = !compositor_->InitializeHwDraw(gl_surface_);
   hardware_initialized_ = true;
 
-  if (hardware_failed_)
+  if (hardware_failed_) {
     gl_surface_ = NULL;
+  }

[joth, 2013/10/02 10:47:01]

intended change?

[boliu, 2013/10/02 14:09:55]

Reverted.

 
   return !hardware_failed_;
 }
@@ -373,8 +405,7 @@ void InProcessViewRenderer::DrawGL(AwDrawGLInfo* draw_info) {
   }
 
   if (draw_info->mode == AwDrawGLInfo::kModeProcess) {
-    TRACE_EVENT_INSTANT0(
-        "android_webview", "EarlyOut_ModeProcess", TRACE_EVENT_SCOPE_THREAD);
+    TRACE_EVENT0("android_webview", "EarlyOut_ModeProcess");
     return;
   }
 
@@ -869,11 +900,15 @@ void InProcessViewRenderer::FallbackTickFired() {
   // This should only be called if OnDraw or DrawGL did not come in time, which
   // means block_invalidates_ must still be true.
   DCHECK(block_invalidates_);
-  if (compositor_needs_continuous_invalidate_ && compositor_) {
-    SkBitmapDevice device(SkBitmap::kARGB_8888_Config, 1, 1);
-    SkCanvas canvas(&device);
-    CompositeSW(&canvas);
-  }
+  if (compositor_needs_continuous_invalidate_ && compositor_)
+    ForceCompositeSW();
+}
+
+void InProcessViewRenderer::ForceCompositeSW() {
+  DCHECK(compositor_);
+  SkBitmapDevice device(SkBitmap::kARGB_8888_Config, 1, 1);
+  SkCanvas canvas(&device);
+  CompositeSW(&canvas);
 }
 
 bool InProcessViewRenderer::CompositeSW(SkCanvas* canvas) {