Redesigns the text input focus handling.

ui/views/controls/webview/webview.cc

Index: ui/views/controls/webview/webview.cc
diff --git a/ui/views/controls/webview/webview.cc b/ui/views/controls/webview/webview.cc
index 4669c3ede4ac7a7827438711ee68e7c71d9de163..c134301b59bce2f5155e2bdcb86b56c4f4f69381 100644
--- a/ui/views/controls/webview/webview.cc
+++ b/ui/views/controls/webview/webview.cc
@@ -14,6 +14,7 @@
 #include "ipc/ipc_message.h"
 #include "ui/accessibility/ax_enums.h"
 #include "ui/accessibility/ax_view_state.h"
+#include "ui/base/ui_base_switches_util.h"
 #include "ui/events/event.h"
 #include "ui/views/accessibility/native_view_accessibility.h"
 #include "ui/views/controls/native/native_view_host.h"
@@ -156,6 +157,19 @@ void WebView::AboutToRequestFocusFromTabTraversal(bool reverse) {
     web_contents()->FocusThroughTabTraversal(reverse);
 }
 
+ui::TextInputClient* WebView::GetTextInputClient() {
+  if (!switches::IsNewTextInputFocusEnabled())

[msw, 2014/03/11 00:58:50]

nit: just make this condition part of the if statement below.

[Yuki, 2014/03/11 15:27:37]

Done.

+    return NULL;
+
+  if (web_contents() && !web_contents()->IsBeingDestroyed()) {
+    content::RenderWidgetHostView* host_view =
+        web_contents()->GetRenderWidgetHostView();
+    if (host_view)
+      return host_view->GetTextInputClient();
+  }
+  return NULL;
+}
+
 void WebView::GetAccessibleState(ui::AXViewState* state) {
   state->role = ui::AX_ROLE_GROUP;
 }
@@ -194,6 +208,15 @@ bool WebView::EmbedsFullscreenWidget() const {
 ////////////////////////////////////////////////////////////////////////////////
 // WebView, content::WebContentsObserver implementation:
 
+void WebView::RenderViewDeleted(content::RenderViewHost* render_view_host) {
+  // WebView::GetTextInputClient() delegates the text input handling to the

[msw, 2014/03/11 00:58:50]

This comment doesn't explain why you'd want to set the focused text input client
to |this| when the underlying render view host is deleted. I'm generally
confused by what's happening here and why.

[Yuki, 2014/03/11 15:27:37]

I've updated the comment trying to make it clearer.

Let me explain in pseudo code.

FocusManager::SetFocusedView(view) {
  TextInputClient* text_input_client = view->GetTextInputClient();
  // Remember the pointer of |text_input_client|.

  // Need to forget the pointer when the object dies.
}

WebView::GetTextInputClient() {
  return rwhv_->GetTextInputClient();
}

WebView::RenderViewDeleted() {
  // This method is called when |rwhv_| was deleted.
  // rwhv_->GetTextInputClient() must have been deleted, too.

  // Note that it's possible that |rwhv_| points to a new RWHV
  // and this WebView is still focused.

  // Tell the focus manager that |this->GetTextInputClient()|
  // will return a new TextInputClient.
  FocusManager->OnTextInputClientChanged(this);
}

[msw, 2014/03/11 23:24:37]

That makes sense, thanks for the explanation and comment.

+  // underlying content::RenderWidgetHostView.  So when it's destroyed, we have
+  // to change the focused text input client.
+  FocusManager* const focus_manager = GetFocusManager();
+  if (focus_manager)
+    focus_manager->OnTextInputClientChanged(this);
+}
+
 void WebView::RenderViewHostChanged(content::RenderViewHost* old_host,
                                     content::RenderViewHost* new_host) {
   FocusManager* const focus_manager = GetFocusManager();