Plugin Power Saver: Fix Dr. Memory leaks in browser tests.

Power Saver Test Plugin triggers Dr. Memory leaks under Windows. Most likely because the test process is destroyed before the out of process test plugin has a chance to free its Pepper resources (an image data).

This is because the test plugin is trying to draw new frames as fast as it possibly can. There's no reason for the test plugin to draw so many frames. In fact, it only needs one.

Changing the test plugin to draw only one frame fixes the issue for me (locally).

BUG=487492

Review URL: https://codereview.chromium.org/1182283002

Cr-Commit-Position: refs/heads/master@{#334407}

ppapi/examples/gamepad/gamepad.cc

@@ -69,6 +69,8 @@ class MyInstance : public pp::Instance {
   }
 
   void OnFlush(int32_t) {
+    // This plugin continuously paints because it continously samples the
+    // gamepad and paints its updated state.
     Paint();
   }
 
@@ -145,4 +147,3 @@ Module* CreateModule() {
 }
 
 }  // namespace pp
-

ppapi/tests/power_saver_test_plugin.cc

@@ -15,11 +15,14 @@
 #undef PostMessage
 #endif
 
+static void DummyCompletionCallback(void*, int32_t) {
+}
+
 // This is a simple C++ Pepper plugin that enables Plugin Power Saver tests.
 class PowerSaverTestInstance : public pp::Instance {
  public:
   explicit PowerSaverTestInstance(PP_Instance instance)
-      : pp::Instance(instance), callback_factory_(this) {}
+      : pp::Instance(instance) {}
   ~PowerSaverTestInstance() override {}
 
   bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
@@ -42,11 +45,11 @@ class PowerSaverTestInstance : public pp::Instance {
     if (!BindGraphics(device_context_))
       return;
 
+    // Since we draw a static image, we only need to make a new frame when
+    // the device is initialized or the view size changes.
     Paint();
   }
 
-  void OnFlush(int32_t) { Paint(); }
-
  private:
   void Paint() {
     pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL,
@@ -64,13 +67,11 @@ class PowerSaverTestInstance : public pp::Instance {
 
     device_context_.ReplaceContents(&image);
     device_context_.Flush(
-        callback_factory_.NewCallback(&PowerSaverTestInstance::OnFlush));
+        pp::CompletionCallback(&DummyCompletionCallback, nullptr));
   }
 
   pp::View view_;
   pp::Graphics2D device_context_;
-
-  pp::CompletionCallbackFactory<PowerSaverTestInstance> callback_factory_;
 };
 
 class PowerSaverTestModule : public pp::Module {

tools/valgrind/drmemory/suppressions_full.txt

@@ -1872,34 +1872,6 @@ content.dll!content::RenderThreadImpl::AllocateSharedMemory
 ...
 content.dll!content::WebGraphicsContext3DCommandBufferImpl::CreateContext
 
-HANDLE LEAK
-name=https://crbug.com/487492
-system call NtCreateSection
-KERNELBASE.dll!CreateFileMappingW
-base.dll!base::SharedMemory::Create
-base.dll!base::SharedMemory::CreateAnonymous
-content.dll!content::ChildThreadImpl::AllocateSharedMemory
-...
-ppapi_proxy.dll!ppapi::proxy::PPB_ImageData_Proxy::CreateImageData
-
-HANDLE LEAK
-name=https://crbug.com/487492_b
-system call NtGdiCreateDIBSection
-GDI32.dll!CreateDIBSection
-skia.dll!`anonymous namespace'::CreateHBitmap
-...
-content.dll!content::PepperGraphics2DHost::Flush
-
-HANDLE LEAK
-name=https://crbug.com/487492_c
-system call NtCreateSection
-KERNELBASE.dll!CreateFileMappingW
-base.dll!base::SharedMemory::Create
-base.dll!base::SharedMemory::CreateAnonymous
-content.dll!content::ChildThreadImpl::AllocateSharedMemory
-...
-content.dll!content::PepperPluginInstanceImpl::PrepareTextureMailbox
-
 HANDLE LEAK
 name=https://crbug.com/489779
 system call NtUserCreateWindowEx