Change the behavior of TSFTextStore::QueryInsert() to support partial commit with Metro MS-IME.

ui/base/ime/win/tsf_text_store.cc

 // Copyright (c) 2012 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.
 
 #define INITGUID  // required for GUID_PROP_INPUTSCOPE
 #include "ui/base/ime/win/tsf_text_store.h"
 
 #include <InputScope.h>
 #include <OleCtl.h>
 
@@ skipping 416 matching lines @@
   selection_.set_end(new_end_pos);
   return S_OK;
 }
 
 STDMETHODIMP TSFTextStore::QueryInsert(
     LONG acp_test_start,
     LONG acp_test_end,
     ULONG text_size,
     LONG* acp_result_start,
     LONG* acp_result_end) {
-  if (!acp_result_start || !acp_result_end)
+  if (!acp_result_start || !acp_result_end || acp_test_start > acp_test_end)
     return E_INVALIDARG;
-  if (!((static_cast<LONG>(committed_size_) <= acp_test_start) &&
-        (acp_test_start <= acp_test_end) &&
-        (acp_test_end <= static_cast<LONG>(string_buffer_.size())))) {
-    return E_INVALIDARG;
-  }
-  *acp_result_start = acp_test_start;
-  *acp_result_end = acp_test_end;
+  const LONG committed_size = static_cast<LONG>(committed_size_);
+  const LONG buffer_size = static_cast<LONG>(string_buffer_.size());
+  *acp_result_start = std::min(std::max(committed_size, acp_test_start),
+                               buffer_size);
+  *acp_result_end = std::min(std::max(committed_size, acp_test_end),
+                             buffer_size);
   return S_OK;
 }
 
 STDMETHODIMP TSFTextStore::QueryInsertEmbedded(const GUID* service,
                                                const FORMATETC* format,
                                                BOOL* insertable) {
   if (!format)
     return E_INVALIDARG;
   // We don't support any embedded objects.
   if (insertable)
@@ skipping 459 matching lines @@
 
 bool TSFTextStore::HasReadLock() const {
   return (current_lock_type_ & TS_LF_READ) == TS_LF_READ;
 }
 
 bool TSFTextStore::HasReadWriteLock() const {
   return (current_lock_type_ & TS_LF_READWRITE) == TS_LF_READWRITE;
 }
 
 }  // namespace ui