A tricky fix for Issue 1845.

This change is a very tricky fix for Issue 1845 in chromium: cant alignt text to the right using right shift and right ctrl.This change consists of two parts listed below.

1. Emulating the implementation of Safari that changes the text-direction of an input element.

Safari uses context menus to change the text direction. This change adds an IPC message 'ViewMsg_SetTextDirection', which notifies the new text direction. Also, it adds two functions: RenderWidgetHost::UpdateTextDirection() and RenderWidgetHost::NotifyTextDirection(). They encapsulate the new IPC message so that we can use them both when we presses a set of keys and when we add context-menu items which change the text direction.

2. Calling the above interface when pressing right-shift and right-control keys, or when left-shift and left-control keys.

This modifies the RenderWidgetHostViewWin::OnKeyEvent() function and call the above text-direction interfaces when a user finishes pressing the keys. As you can imagine, if we send an IPC message every time when we receive a WM_KEYDOWN event, we continue sending IPC messages while a user is pressing the keys.

BUG=1845
Review URL: http://codereview.chromium.org/39252

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@11953 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 73 insertions, 1 deletions

diff --git a/chrome/browser/renderer_host/render_widget_host.cc b/chrome/browser/renderer_host/render_widget_host.cc
index 83d7bcf..f40fe08 100644
--- a/chrome/browser/renderer_host/render_widget_host.cc
+++ b/chrome/browser/renderer_host/render_widget_host.cc
@@ -53,7 +53,9 @@ RenderWidgetHost::RenderWidgetHost(RenderProcessHost* process,
       mouse_move_pending_(false),
       needs_repainting_on_restore_(false),
       is_unresponsive_(false),
-      view_being_painted_(false) {
+      view_being_painted_(false),
+      text_direction_updated_(false),
+      text_direction_(WEB_TEXT_DIRECTION_LTR) {
   if (routing_id_ == MSG_ROUTING_NONE)
     routing_id_ = process_->GetNextRoutingID();
 
@@ -356,6 +358,19 @@ gfx::Rect RenderWidgetHost::GetRootWindowResizerRect() const {
   return gfx::Rect();
 }
 
+void RenderWidgetHost::UpdateTextDirection(WebTextDirection direction) {
+  text_direction_updated_ = true;
+  text_direction_ = direction;
+}
+
+void RenderWidgetHost::NotifyTextDirection() {
+  if (text_direction_updated_) {
+    text_direction_updated_ = false;
+    Send(new ViewMsg_SetTextDirection(routing_id(),
+                                      text_direction_));
+  }
+}
+
 void RenderWidgetHost::Destroy() {
   NotificationService::current()->Notify(
       NotificationType::RENDER_WIDGET_HOST_DESTROYED,
diff --git a/chrome/browser/renderer_host/render_widget_host.h b/chrome/browser/renderer_host/render_widget_host.h
index 59235d0..01bd391 100644
--- a/chrome/browser/renderer_host/render_widget_host.h
+++ b/chrome/browser/renderer_host/render_widget_host.h
@@ -15,6 +15,7 @@
 #include "chrome/common/native_web_keyboard_event.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 #include "webkit/glue/webinputevent.h"
+#include "webkit/glue/webtextdirection.h"
 
 namespace gfx {
 class Rect;
@@ -215,6 +216,38 @@ class RenderWidgetHost : public IPC::Channel::Listener {
   // And to also expose it to the RenderWidgetHostView.
   virtual gfx::Rect GetRootWindowResizerRect() const;
 
+  // Update the text direction of the focused input element and notify it to a
+  // renderer process.
+  // These functions have two usage scenarios: changing the text direction
+  // from a menu (as Safari does), and; changing the text direction when a user
+  // presses a set of keys (as IE and Firefox do).
+  // 1. Change the text direction from a menu.
+  // In this scenario, we receive a menu event only once and we should update
+  // the text direction immediately when a user chooses a menu item. So, we
+  // should call both functions at once as listed in the following snippet.
+  //   void RenderViewHost::SetTextDirection(WebTextDirection direction) {
+  //     UpdateTextDirectioN(direction);
+  //     NotifyTextDirection();
+  //   }
+  // 2. Change the text direction when pressing a set of keys.
+  // Becauses of auto-repeat, we may receive the same key-press event many
+  // times while we presses the keys and it is nonsense to send the same IPC
+  // messsage every time when we receive a key-press event.
+  // To suppress the number of IPC messages, we just update the text direction
+  // when receiving a key-press event and send an IPC message when we release
+  // the keys as listed in the following snippet.
+  //   if (key_event.type == WebKeyboardEvent::KEY_DOWN) {
+  //     if (key_event.windows_key_code == 'A' &&
+  //         key_event.modifiers == WebKeyboardEvent::CTRL_KEY) {
+  //       UpdateTextDirectioN(dir);
+  //     }
+  //   } else if (key_event.type == WebKeyboardEvent::KEY_UP) {
+  //     NotifyTextDirection();
+  //   }
+  // Note: we cannot undo this change because either Firefox or IE cannot.
+  void UpdateTextDirection(WebTextDirection direction);
+  void NotifyTextDirection();
+
  protected:
   // Internal implementation of the public Forward*Event() methods.
   void ForwardInputEvent(const WebInputEvent& input_event, int event_size);
@@ -363,6 +396,10 @@ class RenderWidgetHost : public IPC::Channel::Listener {
   // back to whatever unhandled handler instead of the returned version.
   KeyQueue key_queue_;
 
+  // Set when we need to update the text direction.
+  bool text_direction_updated_;
+  WebTextDirection text_direction_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHost);
 };
 
diff --git a/chrome/browser/renderer_host/render_widget_host_view_win.cc b/chrome/browser/renderer_host/render_widget_host_view_win.cc
index 12dc1ba..52751ea 100644
--- a/chrome/browser/renderer_host/render_widget_host_view_win.cc
+++ b/chrome/browser/renderer_host/render_widget_host_view_win.cc
@@ -823,6 +823,26 @@ LRESULT RenderWidgetHostViewWin::OnKeyEvent(UINT message, WPARAM wparam,
     return ::SendMessage(parent_hwnd_, message, wparam, lparam);
   }
 
+  if (wparam == VK_SHIFT || wparam == VK_CONTROL) {
+    // Bug 1845: we need to update the text direction when a user releases
+    // either a right-shift key or a right-control key after pressing both of
+    // them. So, we just update the text direction while a user is pressing the
+    // keys, and we notify the text direction when a user releases either of
+    // them.
+    if (message == WM_KEYDOWN) {
+      const int kKeyDownMask = 0x8000;
+      if ((GetKeyState(VK_RSHIFT) & kKeyDownMask) &&
+          (GetKeyState(VK_RCONTROL) & kKeyDownMask)) {
+        render_widget_host_->UpdateTextDirection(WEB_TEXT_DIRECTION_RTL);
+      } else if ((GetKeyState(VK_LSHIFT) & kKeyDownMask) &&
+                 (GetKeyState(VK_LCONTROL) & kKeyDownMask)) {
+        render_widget_host_->UpdateTextDirection(WEB_TEXT_DIRECTION_LTR);
+      }
+    } else if (message == WM_KEYUP) {
+      render_widget_host_->NotifyTextDirection();
+    }
+  }
+
   render_widget_host_->ForwardKeyboardEvent(
       NativeWebKeyboardEvent(m_hWnd, message, wparam, lparam));
   return 0;