[PresentationAPI] Implementing send() from WebPresentationClient to the PresentationService.

content/public/common/presentation_constants.cc

Index: content/public/common/presentation_constants.cc
diff --git a/content/public/browser/interstitial_page_delegate.cc b/content/public/common/presentation_constants.cc
similarity index 54%
copy from content/public/browser/interstitial_page_delegate.cc
copy to content/public/common/presentation_constants.cc
index 60a441842b4af1ee688de6c4283e813f016059ec..da7e6acd3766d99187726263e9734dd2f62f623a 100644
--- a/content/public/browser/interstitial_page_delegate.cc
+++ b/content/public/common/presentation_constants.cc
@@ -2,12 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/public/browser/interstitial_page_delegate.h"
+#include "content/public/common/presentation_constants.h"
 
 namespace content {
-InterstitialPageDelegate::TypeID InterstitialPageDelegate::GetTypeForTesting()
-    const {
-  return nullptr;
-}
+
+const size_t kMaxPresentationSessionMessageSize = 64 * 1024; // 64 KB.
 
 }  // namespace content