Eliminate faux-RTTI code from BrowserView.

Use the existing View::AcceleratorPressed() method to invoke a Textfield's
clipboard functions from the browser menu.

BUG=319035
TEST=none

Review URL: https://codereview.chromium.org/1091703002

Cr-Commit-Position: refs/heads/master@{#325781}
diff --git a/chrome/browser/ui/browser_command_controller.cc b/chrome/browser/ui/browser_command_controller.cc
index a7b5229..ac87bb1 100644
--- a/chrome/browser/ui/browser_command_controller.cc
+++ b/chrome/browser/ui/browser_command_controller.cc
@@ -606,13 +606,9 @@
 
     // Clipboard commands
     case IDC_CUT:
-      Cut(browser_);
-      break;
     case IDC_COPY:
-      Copy(browser_);
-      break;
     case IDC_PASTE:
-      Paste(browser_);
+      CutCopyPaste(browser_, id);
       break;
 
     // Find-in-page