[Android WebView] OnMemoryPressure to drop tile memory

android_webview/browser/browser_view_renderer.h

Index: android_webview/browser/browser_view_renderer.h
diff --git a/android_webview/browser/browser_view_renderer.h b/android_webview/browser/browser_view_renderer.h
index 0ae9538484cbafb764625d40288befcba32dc1ca..774ad98fc5f45ffe5e0cb3978ac5705e5b068add 100644
--- a/android_webview/browser/browser_view_renderer.h
+++ b/android_webview/browser/browser_view_renderer.h
@@ -6,6 +6,7 @@
 #define ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_
 
 #include "base/android/scoped_java_ref.h"
+#include "base/memory/memory_pressure_listener.h"
 #include "skia/ext/refptr.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
@@ -117,6 +118,10 @@ class BrowserViewRenderer {
   // The global visible rect changed and this is the new value.
   virtual void SetGlobalVisibleRect(const gfx::Rect& visible_rect) = 0;
 
+  virtual void OnMemoryPressure(
+      base::MemoryPressureListener::MemoryPressureLevel
+          memory_pressure_level) = 0;
+
   // CapturePicture API methods.
   virtual skia::RefPtr<SkPicture> CapturePicture(int width, int height) = 0;
   virtual void EnableOnNewPicture(bool enabled) = 0;