Notify normalizing input filters on blur.

Previously, ReleaseAllKeys was not notifying the normalizing input filter
because that filter exists above InputEventTracker in the input pipeline.
In fact, the input "pipeline" was more like a tree, with both the touch
input scaler and the pepper input handler feeding into the input tracker.

This CL establishes a linear pipeline, as described in the header comment.

BUG=590404

Review URL: https://codereview.chromium.org/1760633003

Cr-Commit-Position: refs/heads/master@{#379398}

2 files changed, 19 insertions, 5 deletions

diff --git a/remoting/protocol/input_event_tracker.cc b/remoting/protocol/input_event_tracker.cc
index 60c4bfd..c232c01 100644
--- a/remoting/protocol/input_event_tracker.cc
+++ b/remoting/protocol/input_event_tracker.cc
@@ -10,9 +10,10 @@
 namespace remoting {
 namespace protocol {
 
+InputEventTracker::InputEventTracker() {}
+
 InputEventTracker::InputEventTracker(InputStub* input_stub)
-    : input_stub_(input_stub),
-      mouse_button_state_(0) {
+    : input_stub_(input_stub) {
 }
 
 InputEventTracker::~InputEventTracker() {}
@@ -26,6 +27,8 @@ int InputEventTracker::PressedKeyCount() const {
 }
 
 void InputEventTracker::ReleaseAll() {
+  DCHECK(input_stub_);
+
   // Release all pressed keys.
   for (auto keycode : pressed_keys_) {
     KeyEvent event;
@@ -91,6 +94,8 @@ void InputEventTracker::ReleaseAllIfModifiersStuck(bool alt_expected,
 }
 
 void InputEventTracker::InjectKeyEvent(const KeyEvent& event) {
+  DCHECK(input_stub_);
+
   // We don't need to track the keyboard lock states of key down events.
   // Pressed keys will be released with |lock_states| set to 0.
   // The lock states of auto generated key up events don't matter as long as
@@ -108,10 +113,13 @@ void InputEventTracker::InjectKeyEvent(const KeyEvent& event) {
 }
 
 void InputEventTracker::InjectTextEvent(const TextEvent& event) {
+  DCHECK(input_stub_);
   input_stub_->InjectTextEvent(event);
 }
 
 void InputEventTracker::InjectMouseEvent(const MouseEvent& event) {
+  DCHECK(input_stub_);
+
   if (event.has_x() && event.has_y()) {
     mouse_pos_ = webrtc::DesktopVector(event.x(), event.y());
   }
@@ -130,6 +138,7 @@ void InputEventTracker::InjectMouseEvent(const MouseEvent& event) {
 }
 
 void InputEventTracker::InjectTouchEvent(const TouchEvent& event) {
+  DCHECK(input_stub_);
   // We only need the IDs to cancel all touch points in ReleaseAll(). Other
   // fields do not have to be tracked here as long as the host keeps track of
   // them.
diff --git a/remoting/protocol/input_event_tracker.h b/remoting/protocol/input_event_tracker.h
index ff19b1d..1511fa5 100644
--- a/remoting/protocol/input_event_tracker.h
+++ b/remoting/protocol/input_event_tracker.h
@@ -23,9 +23,14 @@ namespace protocol {
 // |input_stub| for all currently-pressed keys and buttons when necessary.
 class InputEventTracker : public InputStub {
  public:
-  explicit InputEventTracker(protocol::InputStub* input_stub);
+  InputEventTracker();
+  explicit InputEventTracker(InputStub* input_stub);
   ~InputEventTracker() override;
 
+  void set_input_stub(InputStub* input_stub) {
+    input_stub_ = input_stub;
+  }
+
   // Returns true if the key with the specified USB code is currently pressed.
   bool IsKeyPressed(ui::DomCode usb_keycode) const;
 
@@ -49,12 +54,12 @@ class InputEventTracker : public InputStub {
   void InjectTouchEvent(const TouchEvent& event) override;
 
  private:
-  protocol::InputStub* input_stub_;
+  InputStub* input_stub_ = nullptr;
 
   std::set<ui::DomCode> pressed_keys_;
 
   webrtc::DesktopVector mouse_pos_;
-  uint32_t mouse_button_state_;
+  uint32_t mouse_button_state_ = 0;
 
   std::set<uint32_t> touch_point_ids_;