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();
+    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));
 }