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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "content/browser/renderer_host/touch_smooth_scroll_gesture_android.h"
      6 
      7 #include "base/debug/trace_event.h"
      8 #include "content/browser/renderer_host/render_widget_host_impl.h"
      9 #include "jni/SmoothScroller_jni.h"
     10 
     11 namespace {
     12 bool g_jni_initialized = false;
     13 
     14 void RegisterNativesIfNeeded(JNIEnv* env) {
     15   if (!g_jni_initialized) {
     16     content::RegisterNativesImpl(env);
     17     g_jni_initialized = true;
     18   }
     19 }
     20 }  // namespace
     21 
     22 namespace content {
     23 
     24 TouchSmoothScrollGestureAndroid::TouchSmoothScrollGestureAndroid(
     25     int pixels_to_scroll,
     26     RenderWidgetHost* rwh,
     27     base::android::ScopedJavaLocalRef<jobject> java_scroller)
     28     : pixels_scrolled_(0),
     29       has_started_(false),
     30       has_sent_motion_up_(false),
     31       pixels_to_scroll_(pixels_to_scroll),
     32       rwh_(rwh),
     33       java_scroller_(java_scroller) {
     34   JNIEnv* env = base::android::AttachCurrentThread();
     35   RegisterNativesIfNeeded(env);
     36 }
     37 
     38 TouchSmoothScrollGestureAndroid::~TouchSmoothScrollGestureAndroid() {
     39 }
     40 
     41 bool TouchSmoothScrollGestureAndroid::ForwardInputEvents(
     42     base::TimeTicks now, RenderWidgetHost* host) {
     43   if (!has_started_) {
     44     has_started_ = true;
     45     JNIEnv* env = base::android::AttachCurrentThread();
     46     Java_SmoothScroller_start(
     47         env, java_scroller_.obj(), reinterpret_cast<int>(this));
     48   }
     49 
     50   TRACE_COUNTER_ID1(
     51       "gpu", "smooth_scroll_by_pixels_scrolled", this, pixels_scrolled_);
     52 
     53   return !has_sent_motion_up_;
     54 }
     55 
     56 double TouchSmoothScrollGestureAndroid::GetScrollDelta(
     57     JNIEnv* env, jobject obj, double scale) {
     58   double delta = smooth_scroll_calculator_.GetScrollDelta(
     59       base::TimeTicks::Now(),
     60       RenderWidgetHostImpl::From(rwh_)->GetSyntheticScrollMessageInterval())
     61       * scale;
     62   pixels_scrolled_ += delta;
     63   return delta;
     64 }
     65 
     66 bool TouchSmoothScrollGestureAndroid::HasFinished(JNIEnv* env, jobject obj) {
     67   return pixels_scrolled_ >= pixels_to_scroll_;
     68 }
     69 
     70 void TouchSmoothScrollGestureAndroid::SetHasSentMotionUp(
     71     JNIEnv* env, jobject obj) {
     72   has_sent_motion_up_ = true;
     73 }
     74 
     75 }  // namespace content
     76