Add support for speak properties such as rate to platform specific TTS.

BUG=none.
TEST=Use extension to drive the tts engines on Windows and Mac.  Had key bindings so that verification of:
  decrease rate, increase rate, decrease pitch, increase pitch, decrease volume, and increase volume worked.  Verified that the limits, when reached, did not have any adverse effects.
Review URL: http://codereview.chromium.org/3325021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@59572 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 38 insertions, 0 deletions

diff --git a/chrome/browser/extensions/extension_tts_api_util.cc b/chrome/browser/extensions/extension_tts_api_util.cc
new file mode 100644
index 0000000..ac5d53b
--- /dev/null
+++ b/chrome/browser/extensions/extension_tts_api_util.cc
@@ -0,0 +1,38 @@
+// Copyright (c) 2010 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.
+
+#include "chrome/browser/extensions/extension_tts_api_util.h"
+
+namespace extension_tts_api_util {
+
+// Static.
+bool ReadNumberByKey(DictionaryValue* dict,
+                     const char* key,
+                     double* ret_value) {
+  Value* value;
+  if (!dict->Get(key, &value))
+    return false;
+
+  if (value->IsType(Value::TYPE_INTEGER)) {
+    int int_value;
+    if (!dict->GetInteger(key, &int_value))
+      return false;
+    *ret_value = int_value;
+  } else if (value->IsType(Value::TYPE_REAL)) {
+    if (!dict->GetReal(key, ret_value))
+      return false;
+  } else {
+    return false;
+  }
+  return true;
+}
+
+// Static.
+void AppendSpeakOption(std::string key,
+                       std::string value,
+                       std::string* options) {
+  *options += key + kEqualStr + value + kDelimiter;
+}
+
+}  // namespace extension_tts_api_util.