TrimMemory strategy while offscreenPreRaster is on.

android_webview/browser/shared_renderer_state.cc

Index: android_webview/browser/shared_renderer_state.cc
diff --git a/android_webview/browser/shared_renderer_state.cc b/android_webview/browser/shared_renderer_state.cc
index 1d9874ee2d6c4962b57588e552183b1b29255d76..7fecf87a2c16b24316679a4a98d472f6539c1890 100644
--- a/android_webview/browser/shared_renderer_state.cc
+++ b/android_webview/browser/shared_renderer_state.cc
@@ -287,6 +287,7 @@ void SharedRendererState::DrawGL(AwDrawGLInfo* draw_info) {
 void SharedRendererState::ReleaseHardwareDrawIfNeededOnUI() {
   DCHECK(ui_loop_->BelongsToCurrentThread());
   InsideHardwareReleaseReset auto_inside_hardware_release_reset(this);
+  bool offscreen_pre_raster = browser_view_renderer_->offscreen_pre_raster();
 
   browser_view_renderer_->DetachFunctorFromView();
   bool hardware_initialized = browser_view_renderer_->hardware_enabled();
@@ -300,7 +301,8 @@ void SharedRendererState::ReleaseHardwareDrawIfNeededOnUI() {
       DrawGL(&info);
     }
 
-    browser_view_renderer_->ReleaseHardware();
+    if (!offscreen_pre_raster)
+      browser_view_renderer_->ReleaseHardware();

[boliu, 2015/04/15 00:31:01]

Then this is also skipping ReleaseHardware in detach, which is not right.

Probably need to expose a separate TrimMemory call, then do some refactoring in
this file

[hush (inactive), 2015/04/15 21:35:48]

Yeah. That is a problem. And it actually caused some crashes in my test. Sorry
about that! I just refactored this file.

   }
 
   GLViewRendererManager* manager = GLViewRendererManager::GetInstance();
@@ -313,7 +315,7 @@ void SharedRendererState::ReleaseHardwareDrawIfNeededOnUI() {
     }
   }
 
-  if (hardware_initialized) {
+  if (hardware_initialized && !offscreen_pre_raster) {
     // Flush any invoke functors that's caused by ReleaseHardware.
     browser_view_renderer_->RequestDrawGL(true);
   }