Unit Test for WebView animating in and out of screen

android_webview/browser/browser_view_renderer_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "android_webview/browser/browser_view_renderer.h"
 #include "android_webview/browser/test/rendering_test.h"
 
 namespace android_webview {
 
 class SmokeTest : public RenderingTest {
@@ skipping 41 matching lines @@
 
   void DidDrawOnRT(SharedRendererState* functor) override {
     EndTest();
   }
  private:
   size_t on_draw_count_;
 };
 
 RENDERING_TEST_F(ClearViewTest);
 
+class TestAnimateInAndOutOfScreen : public RenderingTest {
+ public:
+  TestAnimateInAndOutOfScreen() : on_draw_count_(0u) {}
+
+  void StartTest() override {
+    new_constraints_ = ParentCompositorDrawConstraints(
+        false, gfx::Transform(), gfx::Rect(window_->surface_size()));
+    new_constraints_.transform.Scale(2.0, 2.0);
+    browser_view_renderer_->SetContinuousInvalidate(true);
+  }
+
+  void WillOnDraw() override {
+    if (on_draw_count_ == 0u) {
+      // Step 0: A single onDraw on screen. The parent draw constraints
+      // of the BVR will updated to be the initial constraints.
+      browser_view_renderer_->SetContinuousInvalidate(false);
+    }
+    if (on_draw_count_ == 1u) {
+      // Step 1: A single onDrraw off screen. The parent draw constraints of the
+      // BVR will be updated to the new constraints.
+      browser_view_renderer_->PrepareToDraw(gfx::Vector2d(), gfx::Rect());
+    }
+    if (on_draw_count_ == 2u) {
+      // Step 2: A single onDraw onscreen. End the test when the parent
+      // draw constraints of BVR is updated to initial constraints.
+    }
+  }
+
+  void DidOnDraw(bool success) override {
+    EXPECT_TRUE(success);
+    on_draw_count_++;
+    if (on_draw_count_ == 2u) {
+      PostInvalidate();
+    }
+  }
+
+  bool WillDrawOnRT(SharedRendererState* functor,
+                    AwDrawGLInfo& draw_info) override {
+    if (browser_view_renderer_->global_visible_rect_for_testing().IsEmpty())

[boliu, 2015/03/19 20:24:27]

This is not thread safe in general.

I guess you could either add a lock around on_draw_count_, and use that, or keep
a separate count for WillDrawOnRT.

Or...add a method to get the current child frame for testing.

[hush (inactive), 2015/03/19 21:27:57]

Done.

+      return false;
+
+    draw_info.width = window_->surface_size().width();
+    draw_info.height = window_->surface_size().height();
+    draw_info.is_layer = false;
+
+    gfx::Transform transform;
+    if (on_draw_count_ == 1u)
+      transform = new_constraints_.transform;
+
+    transform.matrix().asColMajorf(draw_info.transform);
+    return true;
+  }
+
+  bool DrawConstraintsEquals(
+      const ParentCompositorDrawConstraints& constraints1,
+      const ParentCompositorDrawConstraints& constraints2) {
+    if (constraints1.is_layer != constraints2.is_layer ||
+        constraints1.transform != constraints2.transform)
+      return false;
+
+    return !constraints1.is_layer ||
+           constraints1.surface_rect == constraints2.surface_rect;
+  }
+
+  void ParentDrawConstraintsUpdated(
+      const ParentCompositorDrawConstraints& constraints) override {
+    if (on_draw_count_ == 1u) {

[boliu, 2015/03/19 20:24:27]

nit, use a switch?

then case 2: and default: can have NOTREACHED()

and then don't have to worry about return statements

[hush (inactive), 2015/03/19 21:27:57]

Okay for case 2.
However, there is a race condition for on_draw_count_ being 4. 
Normally you won't get a forth ondraw. But there are times when the hardware
renderer posts identity matrix back to the UI twice, after the webview goes on
screen.
Looks like in that situation the |child_frame_| in hardware renderer has
"new_transform" for 2 frames. I'm not sure why at the moment.
I might have some wrong assumptions about the synchronization model... so I'm
investigating.

+      EXPECT_TRUE(DrawConstraintsEquals(constraints, new_constraints_));
+      return;
+    }
+
+    EXPECT_NE(on_draw_count_, 2u);
+
+    if (on_draw_count_ == 3u) {
+      EXPECT_TRUE(DrawConstraintsEquals(constraints, initial_constraints_));
+      browser_view_renderer_->SetContinuousInvalidate(false);
+      EndTest();
+      return;
+    }
+  }
+
+ private:
+  size_t on_draw_count_;
+  ParentCompositorDrawConstraints initial_constraints_;
+  ParentCompositorDrawConstraints new_constraints_;
+};
+
+RENDERING_TEST_F(TestAnimateInAndOutOfScreen);
+
 }  // namespace android_webview