[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 51f365ae50723c8b6424986eb5b3fcc458f6d001..f629bee6d61406f79b04bd11622f12ab3fdb6ace 100644
--- a/android_webview/browser/in_process_view_renderer.cc
+++ b/android_webview/browser/in_process_view_renderer.cc
@@ -316,6 +316,28 @@ bool InProcessViewRenderer::RequestProcessGL() {
   return client_->RequestDrawGL(NULL);
 }
 
+void InProcessViewRenderer::OnMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  // Nothing to release.
+  if (!attached_to_window_ || !compositor_ || !hardware_initialized_)
+    return;
+
+  // Do not release resources on view we expect to get DrawGL soon.
+  if (view_visible_ && window_visible_)
+    return;
+
+  TRACE_EVENT_INSTANT0(
+      "android_webview", "OnMemoryPressure", TRACE_EVENT_SCOPE_THREAD);
+  ScopedAppGLStateRestore state_restore(ScopedAppGLStateRestore::MODE_ON_TRIM);
+  gpu::InProcessCommandBuffer::ProcessGpuWorkOnCurrentThread();
+  ScopedAllowGL allow_gl;

[joth, 2013/10/01 11:10:46]

GL not valid if this is a 'fake' memory pressure?

Should we use the new "process with GL valid" Runnable thing ?

+
+  content::SynchronousCompositorMemoryPolicy policy;
+  policy.bytes_limit = 0;
+  policy.num_resources_limit = 0;
+  compositor_->SetMemoryPolicy(policy);

[joth, 2013/10/01 11:10:46]

comment this will get set back upward on the next draw?

+}
+
 void InProcessViewRenderer::UpdateCachedGlobalVisibleRect() {
   client_->UpdateGlobalVisibleRect();
 }