From 95dafbe6316f9c77a1210af211f9eba8136496e4 Mon Sep 17 00:00:00 2001
From: Randall Barker <rbarker@mozilla.com>
Date: Tue, 7 Feb 2017 14:44:43 -0800
Subject: [PATCH] Bug 1336929 - Have UiCompositorControllerChild cache surface
 resize when not yet initialized. r=jchen,dvander

---
 .../ipc/UiCompositorControllerChild.cpp       | 56 +++++++++++++++++++
 gfx/layers/ipc/UiCompositorControllerChild.h  |  3 +-
 widget/android/nsWindow.cpp                   |  8 ++-
 3 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/gfx/layers/ipc/UiCompositorControllerChild.cpp b/gfx/layers/ipc/UiCompositorControllerChild.cpp
index 1c902e093735..ec4d914a0605 100644
--- a/gfx/layers/ipc/UiCompositorControllerChild.cpp
+++ b/gfx/layers/ipc/UiCompositorControllerChild.cpp
@@ -18,6 +18,50 @@ static bool sInitialized = false;
 static StaticRefPtr<UiCompositorControllerChild> sChild;
 static StaticRefPtr<UiCompositorControllerParent> sParent;
 
+namespace {
+
+struct SurfaceResizeCache {
+  int32_t mSurfaceWidth;
+  int32_t mSurfaceHeight;
+
+  SurfaceResizeCache(int32_t aWidth, int32_t aHeight) :
+    mSurfaceWidth(aWidth),
+    mSurfaceHeight(aHeight) {}
+
+  SurfaceResizeCache(const SurfaceResizeCache& value)
+  {
+    *this = value;
+  }
+
+  SurfaceResizeCache& operator=(const SurfaceResizeCache& value)
+  {
+    mSurfaceWidth = value.mSurfaceWidth;
+    mSurfaceHeight = value.mSurfaceHeight;
+    return *this;
+  }
+
+  SurfaceResizeCache() :
+    mSurfaceWidth(0),
+    mSurfaceHeight(0) {}
+};
+
+static std::map<int64_t, SurfaceResizeCache> sResizeCache;
+
+static void
+DoCachedResize()
+{
+  MOZ_ASSERT(sChild);
+  MOZ_ASSERT(sChild->IsOnUiThread());
+
+  for (auto& cache : sResizeCache) {
+    sChild->SendResumeAndResize(cache.first, cache.second.mSurfaceWidth, cache.second.mSurfaceHeight);
+  }
+
+  sResizeCache.empty();
+}
+
+} // namespace
+
 UiCompositorControllerChild::UiCompositorControllerChild(RefPtr<nsThread> aThread, const uint64_t& aProcessToken)
  : mUiThread(aThread),
    mProcessToken(aProcessToken)
@@ -83,6 +127,16 @@ UiCompositorControllerChild::InitWithGPUProcess(RefPtr<nsThread> aThread,
   aThread->Dispatch(task.forget(), nsIThread::DISPATCH_NORMAL);
 }
 
+/* static */ void
+UiCompositorControllerChild::CacheSurfaceResize(int64_t aId, int32_t aWidth, int32_t aHeight)
+{
+  // This should only be called if the sChild has not been set yet.
+  // It should also only be called from the UI thread but since the sChild hasn't been set
+  // yet, there isn't a good way to verify this.
+  MOZ_ASSERT(!sChild);
+  sResizeCache[aId] = SurfaceResizeCache{aWidth, aHeight};
+}
+
 void
 UiCompositorControllerChild::OpenForSameProcess()
 {
@@ -99,6 +153,7 @@ UiCompositorControllerChild::OpenForSameProcess()
 
   AddRef();
   sChild = this;
+  DoCachedResize();
 }
 
 void
@@ -118,6 +173,7 @@ UiCompositorControllerChild::OpenForGPUProcess(Endpoint<PUiCompositorControllerC
 
   AddRef();
   sChild = this;
+  DoCachedResize();
 }
 
 void
diff --git a/gfx/layers/ipc/UiCompositorControllerChild.h b/gfx/layers/ipc/UiCompositorControllerChild.h
index 709ceb6daad1..d3882095e8e5 100644
--- a/gfx/layers/ipc/UiCompositorControllerChild.h
+++ b/gfx/layers/ipc/UiCompositorControllerChild.h
@@ -26,6 +26,7 @@ public:
                                  const uint64_t& aProcessToken,
                                  Endpoint<PUiCompositorControllerChild>&& aEndpoint);
 
+  static void CacheSurfaceResize(int64_t aId, int32_t aWidth, int32_t aHeight);
   void Close();
 
   void ActorDestroy(ActorDestroyReason aWhy) override;
@@ -34,12 +35,12 @@ public:
 
   virtual void HandleFatalError(const char* aName, const char* aMsg) const override;
 
+  bool IsOnUiThread() const;
 private:
   UiCompositorControllerChild(RefPtr<nsThread> aThread, const uint64_t& aProcessToken);
   ~UiCompositorControllerChild();
   void OpenForSameProcess();
   void OpenForGPUProcess(Endpoint<PUiCompositorControllerChild>&& aEndpoint);
-  bool IsOnUiThread() const;
 
   RefPtr<nsThread> mUiThread;
   uint64_t mProcessToken;
diff --git a/widget/android/nsWindow.cpp b/widget/android/nsWindow.cpp
index 204a1eacffe7..b5f9f10e380d 100644
--- a/widget/android/nsWindow.cpp
+++ b/widget/android/nsWindow.cpp
@@ -1176,11 +1176,13 @@ public:
         RefPtr<UiCompositorControllerChild> child = UiCompositorControllerChild::Get();
 
         if (!child) {
-            return;
+            // When starting, sometimes the UiCompositorControllerChild is still initializing
+            // so cache the resized surface dimensions until it has initialized.
+            UiCompositorControllerChild::CacheSurfaceResize(id, aWidth, aHeight);
+        } else {
+            child->SendResumeAndResize(id, aWidth, aHeight);
         }
 
-        child->SendResumeAndResize(id, aWidth, aHeight);
-
         mCompositorPaused = false;
 
         class OnResumedEvent : public nsAppShell::Event