Simplify content_layer attachment and viewporting logic.

chrome/browser/android/compositor/scene_layer/static_tab_scene_layer.cc

 // Copyright 2015 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 "chrome/browser/android/compositor/scene_layer/static_tab_scene_layer.h"
 
 #include "cc/layers/layer.h"
 #include "chrome/browser/android/compositor/layer/content_layer.h"
 #include "chrome/browser/android/compositor/layer_title_cache.h"
 #include "chrome/browser/android/compositor/tab_content_manager.h"
@@ skipping 39 matching lines @@
     jint default_background_color,
     jfloat x,
     jfloat y,
     jfloat width,
     jfloat height,
     jfloat content_offset_y,
     jfloat static_to_view_blend,
     jfloat saturation,
     jfloat brightness) {
   background_color_ = default_background_color;
-  gfx::Size content_viewport_size(content_viewport_width,
-                                  content_viewport_height);
-  gfx::Point content_viewport_offset(content_viewport_x, content_viewport_y);
   if (!content_layer_.get()) {
     android::TabContentManager* tab_content_manager =
         android::TabContentManager::FromJavaObject(jtab_content_manager);
     content_layer_ = android::ContentLayer::Create(tab_content_manager);
     layer_->AddChild(content_layer_->layer());
   }
 
   // Only override the alpha of content layers when the static tab is first
   // assigned to the layer tree.
   float content_alpha_override = 1.f;
   bool should_override_content_alpha = last_set_tab_id_ != id;
   last_set_tab_id_ = id;
 
-  // Set up the content layer and move it to the proper position.
-  content_layer_->layer()->SetBounds(gfx::Size(width, height));
-  content_layer_->layer()->SetPosition(gfx::PointF(x, y));
   content_layer_->SetProperties(
       id, can_use_live_layer, static_to_view_blend,
       should_override_content_alpha, content_alpha_override, saturation,
-      gfx::Rect(content_viewport_size), content_viewport_size);
+      false, gfx::Rect());
 
-  gfx::Size content_bounds(0, 0);
-  content_bounds = content_layer_->layer()->bounds();
-
-  gfx::Size actual_content_size(content_layer_->GetContentSize());
-
-  bool view_and_content_have_same_orientation =
-      (content_viewport_size.width() > content_viewport_size.height()) ==
-          (actual_content_size.width() > actual_content_size.height()) &&
-      actual_content_size.width() > 0 && actual_content_size.height() > 0 &&
-      content_viewport_size.width() > 0 && content_viewport_size.height() > 0;
-
-  // This may not be true for frames during rotation.
-  bool content_has_consistent_width =
-      actual_content_size.width() == content_bounds.width() &&
-      actual_content_size.width() == content_viewport_size.width();
-
-  if (view_and_content_have_same_orientation ||
-      (content_has_consistent_width && content_layer_->ShowingLiveLayer())) {
-    y += content_offset_y;
-  } else {
-    // If our orientations are off and we have a static texture, or if we have
-    // a live layer of an unexpected width, move the texture in by the
-    // appropriate amount.
-    x += content_viewport_offset.x();
-    y += content_viewport_offset.y();
-  }
+  x += content_viewport_x;

[Changwan Ryu, 2016/12/12 07:38:04]

Probably content_viewport_x is always 0 here. If that is the case, we don't need
to have this line. (Otherwise, I think we may need a comment explaining why
we're only adding viewport_x.)

[aelias_OOO_until_Jul13, 2016/12/13 02:16:05]

OK, removed this addition as you're right it doesn't do anything and is
inconsistent now.

+  y += content_offset_y;

[Changwan Ryu, 2016/12/12 07:38:04]

This is a great reduction. But now we're passing lots of parameters that aren't
used. How about removing the following parameters?

(content_viewport_x)
content_viewport_y
content_viewport_width
content_viewport_height
width
height

[aelias_OOO_until_Jul13, 2016/12/13 02:16:05]

Done.  I also removed content_offset_y and added it to "y" in Java.

 
   content_layer_->layer()->SetPosition(gfx::PointF(x, y));
   content_layer_->layer()->SetIsDrawable(true);
 
   // Only applies the brightness filter if the value has changed and is less
   // than 1.
   if (brightness != brightness_) {
     brightness_ = brightness;
     cc::FilterOperations filters;
     if (brightness_ < 1.f)
       filters.Append(cc::FilterOperation::CreateBrightnessFilter(brightness_));
     layer_->SetFilters(filters);
   }
 }
 
 static jlong Init(JNIEnv* env, const JavaParamRef<jobject>& jobj) {
   // This will automatically bind to the Java object and pass ownership there.
   StaticTabSceneLayer* scene_layer = new StaticTabSceneLayer(env, jobj);
   return reinterpret_cast<intptr_t>(scene_layer);
 }
 
 bool RegisterStaticTabSceneLayer(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace android