1 files changed, 67 insertions, 0 deletions
diff --git a/net/base/request_priority.cc b/net/base/request_priority.cc
new file mode 100644
index 0000000..dfe083c
--- /dev/null
+++ b/net/base/request_priority.cc
@@ -0,0 +1,67 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/base/request_priority.h"
+#include "base/logging.h"
+
+namespace net {
+
+RequestPriority DetermineRequestPriority(ResourceType::Type type)
+{
+  //__android_log_print(ANDROID_LOG_VERBOSE, "Preload",  "DetermineRequestPriority, type = %d", type);
+
+  // Determine request priority based on how critical this resource typically
+  // is to user-perceived page load performance. Important considerations are:
+  // * Can this resource block the download of other resources.
+  // * Can this resource block the rendering of the page.
+  // * How useful is the page to the user if this resource is not loaded yet.
+  switch (type) {
+    // Main frames are the highest priority because they can block nearly every
+    // type of other resource and there is no useful display without them.
+    // Sub frames are a close second, however it is a common pattern to wrap
+    // ads in an iframe or even in multiple nested iframes. It is worth
+    // investigating if there is a better priority for them.
+    case ResourceType::MAIN_FRAME:
+    case ResourceType::SUB_FRAME:
+      return HIGHEST;
+
+    // Stylesheets and scripts can block rendering and loading of other
+    // resources. Fonts can block text from rendering.
+    case ResourceType::STYLESHEET:
+    case ResourceType::SCRIPT:
+    case ResourceType::FONT_RESOURCE:
+      return MEDIUM;
+
+    // Sub resources, objects and media are lower priority than potentially
+    // blocking stylesheets, scripts and fonts, but are higher priority than
+    // images because if they exist they are probably more central to the page
+    // focus than images on the page.
+    case ResourceType::SUB_RESOURCE:
+    case ResourceType::OBJECT:
+    case ResourceType::MEDIA:
+    case ResourceType::WORKER:
+    case ResourceType::SHARED_WORKER:
+      return LOW;
+
+    // Images are the "lowest" priority because they typically do not block
+    // downloads or rendering and most pages have some useful content without
+    // them.
+    case ResourceType::IMAGE:
+      return LOWEST;
+
+    // Prefetches are at a lower priority than even LOWEST, since they
+    // are not even required for rendering of the current page.
+    case ResourceType::PREFETCH:
+      return IDLE;
+
+    default:
+      // When new resource types are added, their priority must be considered.
+      NOTREACHED();
+      return LOW;
+  }
+}
+
+}  // namespace net
+