Add Generic Implementation of ClipboardRecentContent

components/open_from_clipboard/clipboard_recent_content.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.
 
 #include "components/open_from_clipboard/clipboard_recent_content.h"
 
+#include "url/url_constants.h"
+
 namespace {
 ClipboardRecentContent* g_clipboard_recent_content = nullptr;
-}
+
+// Schemes appropriate for suggestion by ClipboardRecentContent.
+const char* kAuthorizedSchemes[] = {
+    url::kAboutScheme, url::kDataScheme, url::kHttpScheme, url::kHttpsScheme,
+    // TODO(mpearson): add support for chrome:// URLs.  Right now the scheme
+    // for that lives in content and is accessible via
+    // GetEmbedderRepresentationOfAboutScheme() or content::kChromeUIScheme
+    // TODO(mpearson): when adding desktop support, add kFileScheme, kFtpScheme,
+    // and kGopherScheme.
+};
+
+}  // namespace
+
+const base::TimeDelta ClipboardRecentContent::kMaximumAgeOfClipboard =

[dcheng, 2017/04/02 05:04:03]

Does this generate a static initializer? (The constructor is constexpr, but I'm
not sure what happens since the actual static variable isn't marked constexpr)

[Mark P, 2017/04/02 05:33:56]

Changed to constexpr.

+    base::TimeDelta::FromHours(3);
 
 ClipboardRecentContent::ClipboardRecentContent() {}
 
 ClipboardRecentContent::~ClipboardRecentContent() {}
 
 // static
 ClipboardRecentContent* ClipboardRecentContent::GetInstance() {
   return g_clipboard_recent_content;
 }
 
 // static
 void ClipboardRecentContent::SetInstance(ClipboardRecentContent* instance) {
   g_clipboard_recent_content = instance;
 }
+
+// static
+bool ClipboardRecentContent::IsAppropriateSuggestion(const GURL& url) {
+  // Check to make sure it's a scheme we're willing to suggest.
+  for (size_t i = 0; i < arraysize(kAuthorizedSchemes); ++i) {

[dcheng, 2017/04/02 05:04:03]

Alternatively:

for (const auto* authorized_scheme : kAuthorizedSchemes) {
  if (url.SchemeIs(authorized_scheme)) return true;
}

[Mark P, 2017/04/02 05:33:56]

Nice.  Done.

+    if (url.SchemeIs(kAuthorizedSchemes[i]))
+      return true;
+  }
+
+  // Not a scheme we're allowed to return.
+  return false;
+}