Update rewrite_to_chrome_style tool to also rename methods.

tools/clang/rewrite_to_chrome_style/tests/functions-expected.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 namespace blink {
 
 // Tests that the prototype for a function is updated.
 int TestFunctionThatTakesTwoInts(int x, int y);
 
 // Test that the actual function definition is also updated.
 int TestFunctionThatTakesTwoInts(int x, int y) {
   if (x == 0)
     return y;
   // Calls to the function also need to be updated.
   return TestFunctionThatTakesTwoInts(x - 1, y + 1);
 }
 
 // Note: F is already Google style and should not change.
 void F() {
   // Test referencing a function without calling it.
   int (*function_pointer)(int, int) = &TestFunctionThatTakesTwoInts;
 }
 
 }  // namespace blink
+
+void G() {
+  TestFunctionThatTakesTwoInts::TestFunctionThatTakesTwoInts(1, 2);

[danakj, 2016/01/06 22:09:40]

this did the wrong thing? why not blink::TestFunction...

[dcheng, 2016/01/08 01:41:11]

So it turns out that a CallExpr wraps a callee expression: a DeclRefExpr (in the
case of a non-method call) or a MemberExpr (in the case of a method call).

The AST matchers were thus running twice:
- The matcher for CallExpr runs and generates a replacement to change blink ->
TestFunctionThatTakesTwoInts.
- Then the matcher for DeclRefExpr runs and generates a replacement to change
testFunctionThatTakesTwoInts -> TestFunctionThatTakesTwoInts.

The problem is CallExpr's target traits used Expr::getExprLoc(), which is a very
generic 'get me the SourceLocation' function. I looked at a bunch of methods on
CallExpr to see if there was an easy way to get the 'right' SourceLocation.
CallExpr::getCallee() to get to the underlying DeclRefExpr/MemberExpr... but
after looking at the implementation of getCalleeDecl() [1], I decided that this
was much too complicated.

Instead, I've updated the tool: the tool no longer uses the callExpr matchers at
all, instead preferring to match the callee expression inside directly to
generate the replacement. This gives the matcher enough information to always
skip the nested-name specifier.

[1] http://clang.llvm.org/doxygen/Expr_8cpp_source.html#l01186

+}