[Android] Select text when stylus first button is pressed.

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index f4217357c753379b26a0ac67d7a27ff0d0c22425..df07b0fac7f5806e94319f57b22929753ae9fbbe 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -61,6 +61,7 @@
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "ui/base/android/window_android.h"
 #include "ui/base/android/window_android_compositor.h"
+#include "ui/events/event_constants.h"
 #include "ui/events/gesture_detection/gesture_config_helper.h"
 #include "ui/events/gesture_detection/motion_event.h"
 #include "ui/gfx/android/device_display_info.h"
@@ -194,7 +195,8 @@ RenderWidgetHostViewAndroid::RenderWidgetHostViewAndroid(
                                         widget_host->GetRoutingID()) != NULL),
       frame_evictor_(new DelegatedFrameEvictor(this)),
       locks_on_frame_count_(0),
-      observing_root_window_(false) {
+      observing_root_window_(false),
+      gesture_text_selection_triggered_(false) {
   host_->SetView(this);
   SetContentViewCore(content_view_core);
   ImageTransportFactoryAndroid::AddObserver(this);
@@ -553,6 +555,23 @@ void RenderWidgetHostViewAndroid::OnSmartClipDataExtracted(
     content_view_core_->OnSmartClipDataExtracted(result);
 }
 
+bool RenderWidgetHostViewAndroid::ShouldTriggerOrUntriggerTextSelection(
+    const ui::MotionEvent& event) {
+  // Currently we aren't supporting stylus + touch case.
+  if (event.GetPointerCount() == 0 ||

[jdduke (slow), 2014/06/23 15:09:59]

Nit: GetPointerCount() should never be 0, so I would make this a DCHECK.

[Changwan Ryu, 2014/06/24 09:29:48]

Done.

+      event.GetToolType(0) != ui::MotionEvent::TOOL_TYPE_STYLUS)
+    return false;
+  const bool is_button_pressed =

[jdduke (slow), 2014/06/23 15:09:59]

Maybe rename to |is_secondary_button_pressed|?

[Changwan Ryu, 2014/06/24 09:29:48]

Done.

+      (event.GetButtonState() & ui::MotionEvent::BUTTON_SECONDARY) != 0;
+  const bool is_action_up = event.GetAction() == ui::MotionEvent::ACTION_UP;

[jdduke (slow), 2014/06/23 15:09:59]

Hmm, this is a little confusing, why do we check for ACTION_UP when this
function is only called in the if (ACTION_DOWN) case? I think we can remove this
check and just check the tool type and the secondary button state, and make this
function static (or rather, just move it to the anonymous namespace).

[Changwan Ryu, 2014/06/24 09:29:48]

Done.

+  return (is_button_pressed && !is_action_up) ||
+      (!is_button_pressed && gesture_text_selection_triggered_ && is_action_up);
+}
+
+bool RenderWidgetHostViewAndroid::IsGestureTextSelectionTriggered() const {
+  return gesture_text_selection_triggered_;
+}
+
 bool RenderWidgetHostViewAndroid::OnTouchEvent(
     const ui::MotionEvent& event) {
   if (!host_)
@@ -561,6 +580,20 @@ bool RenderWidgetHostViewAndroid::OnTouchEvent(
   if (!gesture_provider_.OnTouchEvent(event))
     return false;
 
+  if (event.GetAction() == ui::MotionEvent::ACTION_DOWN) {
+    gesture_text_selection_triggered_ =
+        ShouldTriggerOrUntriggerTextSelection(event);
+  }
+
+  if (gesture_text_selection_triggered_) {
+    const bool event_consumed = false;
+    gesture_provider_.OnTouchEventAck(event_consumed);
+    if (event.GetAction() == ui::MotionEvent::ACTION_UP ||

[jdduke (slow), 2014/06/23 15:09:59]

As I said, we can't reset the state using ACTION_UP and ACTION_CANCEL, because
there are timeout events like GESTURE_TAP that might get triggered after an
ACTION_UP (because of the 300ms tap delay on desktop sites).  It should be
sufficient to reset the flag only on ACTION_DOWN.

[Changwan Ryu, 2014/06/24 09:29:48]

Removed.

+        event.GetAction() == ui::MotionEvent::ACTION_CANCEL)
+      gesture_text_selection_triggered_ = false;
+    return true;
+  }
+
   // Short-circuit touch forwarding if no touch handlers exist.
   if (!host_->ShouldForwardTouchEvent()) {
     const bool event_consumed = false;
@@ -1290,6 +1323,14 @@ void RenderWidgetHostViewAndroid::RunAckCallbacks() {
 
 void RenderWidgetHostViewAndroid::OnGestureEvent(
     const ui::GestureEventData& gesture) {
+  if (gesture_text_selection_triggered_) {
+    if (gesture.type() == ui::ET_GESTURE_LONG_PRESS) {
+      // Exits the text selection mode until ACTION_DOWN resets it.
+      gesture_text_selection_triggered_ = false;

[jdduke (slow), 2014/06/23 15:09:59]

Hmm, I don't think we want to reset this here. Can't we just send a SelectWord
message or something to that effect?

[Changwan Ryu, 2014/06/24 09:29:48]

Fixed to call SelectWord instead.
But reset is still needed because action_move events will most likely happen
after a long press, and those events will reselect or unselect text.

+    } else {
+      return;

[jdduke (slow), 2014/06/23 15:09:59]

I thought Samsung wanted to be able to highlight a word using either TAP or
LONG_PRESS? Is that not the case? 

[Changwan Ryu, 2014/06/24 09:29:48]

Samsung confirmed that it's only for LONG PRESS.

+    }
+  }
   SendGestureEvent(CreateWebGestureEventFromGestureEventData(gesture));
 }