Adds selection expansion support for Contextual Search.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index bb881cbbd0bdf2581d61e758bd9e8c9974b8a082..bdf5e2ab76d66a3782e9cc88a0ffd43d98adbe70 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -1357,6 +1357,8 @@ bool RenderViewImpl::OnMessageReceived(const IPC::Message& message) {
                         OnReleaseDisambiguationPopupBitmap)
     IPC_MESSAGE_HANDLER(ViewMsg_ForceRedraw, OnForceRedraw)
     IPC_MESSAGE_HANDLER(ViewMsg_SelectWordAroundCaret, OnSelectWordAroundCaret)
+    IPC_MESSAGE_HANDLER(ViewMsg_ExpandSelectionByCharacterOffset,
+                        OnExpandSelectionByCharacterOffset)
 #if defined(OS_ANDROID)
     IPC_MESSAGE_HANDLER(InputMsg_ActivateNearestFindResult,
                         OnActivateNearestFindResult)
@@ -1393,6 +1395,25 @@ void RenderViewImpl::OnSelectWordAroundCaret() {
   handling_input_event_ = false;
 }
 
+void RenderViewImpl::OnExpandSelectionByCharacterOffset(int start_adjust,
+                                                        int end_adjust) {
+  if (!webview())
+    return;
+
+  handling_input_event_ = true;
+  size_t start, length;
+  if (webview()->caretOrSelectionRange(&start, &length)) {
+    start -= start_adjust;
+    length += end_adjust + start_adjust;
+    WebLocalFrame* web_local_frame =
+        webview()->focusedFrame()->toWebLocalFrame();

[pedro (no code reviews), 2015/07/01 22:18:57]

Please confirm with someone familiar with the WebView if we really need
toWebLocalFrame(), or if we could use instead just focusedFrame() like we do
above for OnSelectWordAroundCaret(). Mounir mentioned that some things are
moving the the local frame, but I don't really understand the difference of the
two.

[aurimas (slooooooooow), 2015/07/01 23:05:44]

Do you have suggestions about who to ask to review this?

[pedro (no code reviews), 2015/07/02 00:09:57]

I would say yoichio@ since he is the one who suggested using this approach:
https://code.google.com/p/chromium/issues/detail?id=396738#c20

+    web_local_frame->selectRange(WebRange::fromDocumentRange(web_local_frame,
+                                                             start,
+                                                             length));
+  }
+  handling_input_event_ = false;
+}
+
 void RenderViewImpl::OnCopyImageAt(int x, int y) {
   webview()->copyImageAt(WebPoint(x, y));
 }