Unify Android Webview and Chrome's fling

android_webview/native/aw_contents.cc

 // Copyright 2012 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/native/aw_contents.h"
 
 #include <limits>
 
 #include "android_webview/browser/aw_browser_context.h"
 #include "android_webview/browser/aw_browser_main_parts.h"
@@ skipping 920 matching lines @@
 void AwContents::FocusFirstNode(JNIEnv* env, jobject obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   web_contents_->FocusThroughTabTraversal(false);
 }
 
 void AwContents::SetBackgroundColor(JNIEnv* env, jobject obj, jint color) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   render_view_host_ext_->SetBackgroundColor(color);
 }
 
+void AwContents::OnComputeScroll(JNIEnv* env,
+                                 jobject obj,
+                                 jlong animation_time_millis) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  browser_view_renderer_.OnComputeScroll(
+      base::TimeTicks() +
+      base::TimeDelta::FromMilliseconds(animation_time_millis));

[boliu, 2015/05/29 19:42:47]

Does this addition make sense?

Documentation on currentAnimationTimeMillis says it is *not* the "wall" clock.

[hush (inactive), 2015/06/05 21:47:22]

I am not exactly sure here. We have confusing usage of time related functions,
some of which are wrong in my opinion.

For example, I looked at some example in ContentViewCore.java where we pass
SystemClock.uptimeMillis() to construct a WebInputEvent. According to
documentation here:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...
You are supposed to pass the time since epoch, so SystemClock.currentTimeMillis
is the right one.
I filed crbug.com/497323 for it.

For the comment about currentAnimationTimeMillis, I think it is right by looking
at the code. What's important for the animation tick is the difference between
each tick, but not the absolute value of each timer tick. We're consistently
passing currentAnimationTimeMillis to InputHandlerProxy to tick the animation.
So we're fine.
https://code.google.com/p/chromium/codesearch#chromium/src/content/renderer/i...

+}
+
 jlong AwContents::ReleasePopupAwContents(JNIEnv* env, jobject obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   return reinterpret_cast<intptr_t>(pending_contents_.release());
 }
 
 gfx::Point AwContents::GetLocationOnScreen() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
   if (obj.is_null())
     return gfx::Point();
   std::vector<int> location;
   base::android::JavaIntArrayToIntVector(
       env,
       Java_AwContents_getLocationOnScreen(env, obj.obj()).obj(),
       &location);
   return gfx::Point(location[0], location[1]);
 }
 
 void AwContents::ScrollContainerViewTo(gfx::Vector2d new_value) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
   if (obj.is_null())
     return;
   Java_AwContents_scrollContainerViewTo(
       env, obj.obj(), new_value.x(), new_value.y());
 }
 
-bool AwContents::IsFlingActive() const {
+bool AwContents::IsSmoothScrollingActive() const {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
   if (obj.is_null())
     return false;
-  return Java_AwContents_isFlingActive(env, obj.obj());
+  return Java_AwContents_isSmoothScrollingActive(env, obj.obj());
 }
 
 void AwContents::UpdateScrollState(gfx::Vector2d max_scroll_offset,
                                    gfx::SizeF contents_size_dip,
                                    float page_scale_factor,
                                    float min_page_scale_factor,
                                    float max_page_scale_factor) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
   if (obj.is_null())
     return;
   Java_AwContents_updateScrollState(env,
                                     obj.obj(),
                                     max_scroll_offset.x(),
                                     max_scroll_offset.y(),
                                     contents_size_dip.width(),
                                     contents_size_dip.height(),
                                     page_scale_factor,
                                     min_page_scale_factor,
                                     max_page_scale_factor);
 }
 
-void AwContents::DidOverscroll(gfx::Vector2d overscroll_delta) {
+void AwContents::DidOverscroll(gfx::Vector2d overscroll_delta,
+                               gfx::Vector2dF overscroll_velocity) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
   if (obj.is_null())
     return;
-  Java_AwContents_didOverscroll(
-      env, obj.obj(), overscroll_delta.x(), overscroll_delta.y());
+  Java_AwContents_didOverscroll(env, obj.obj(), overscroll_delta.x(),
+                                overscroll_delta.y(), overscroll_velocity.x(),
+                                overscroll_velocity.y());
 }
 
 void AwContents::SetDipScale(JNIEnv* env, jobject obj, jfloat dip_scale) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   SetDipScaleInternal(dip_scale);
 }
 
 void AwContents::SetDipScaleInternal(float dip_scale) {
   browser_view_renderer_.SetDipScale(dip_scale);
 }
@@ skipping 145 matching lines @@
 
   AwMessagePortServiceImpl::GetInstance()->CreateMessageChannel(env, ports,
       GetMessagePortMessageFilter());
 }
 
 void SetShouldDownloadFavicons(JNIEnv* env, jclass jclazz) {
   g_should_download_favicons = true;
 }
 
 }  // namespace android_webview