Adds selection expansion support for Contextual Search.

content/common/input_messages.h

Index: content/common/input_messages.h
diff --git a/content/common/input_messages.h b/content/common/input_messages.h
index ea76042e791e81a7e539895dffc457a95ed7d306..2a063dd117417c331431f3fc1d8d0d42c83094f0 100644
--- a/content/common/input_messages.h
+++ b/content/common/input_messages.h
@@ -214,6 +214,14 @@ IPC_MESSAGE_ROUTED2(InputMsg_SelectRange,
                     gfx::Point /* base */,
                     gfx::Point /* extent */)
 
+// Sent by the browser to ask the renderer to adjust the selection start and
+// end points by the given amounts. A negative amount moves the selection
+// towards the beginning of the document, a positive amount moves the selection
+// towards the end of the document.
+IPC_MESSAGE_ROUTED2(InputMsg_AdjustSelectionByCharacterOffset,
+                    int /* start_adjust*/,
+                    int /* end_adjust */)
+
 // Requests the renderer to move the selection extent point to a new position.
 // Expects a MoveRangeSelectionExtent_ACK message when finished.
 IPC_MESSAGE_ROUTED1(InputMsg_MoveRangeSelectionExtent,