Histograms & Field Trails about prefetching

This CL lands some histograms to track prefetching, and a 10% field trial
enabling the feature to track performance.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/3036050

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55431 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 14 insertions, 13 deletions

diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 32cbdca..4df9c3c 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -129,6 +129,11 @@ const char kDisableBackingStoreLimit[]      = "disable-backing-store-limit";
 // Disable support for cached byte-ranges.
 const char kDisableByteRangeSupport[]       = "disable-byte-range-support";
 
+// Disable requests that webkit labels TargetIsPrefetch.  As of
+// writing only <link rel=prefetch...> but also eventually
+// Link: headers.
+const char kDisableContentPrefetch[]        = "disable-content-prefetch";
+
 // Disables the custom JumpList on Windows 7.
 const char kDisableCustomJumpList[]         = "disable-custom-jumplist";
 
@@ -165,7 +170,7 @@ const char kDisableInternalFlash[]          = "disable-internal-flash";
 const char kDisableIPv6[]                   = "disable-ipv6";
 
 // Disable speculative TCP/IP preconnection.
-const char kDisablePreconnect[]              = "disable-preconnect";
+const char kDisablePreconnect[]             = "disable-preconnect";
 
 // Don't execute JavaScript (browser JS like the new tab page still runs).
 const char kDisableJavaScript[]             = "disable-javascript";
@@ -193,11 +198,6 @@ const char kDisablePlugins[]                = "disable-plugins";
 // Disable pop-up blocking.
 const char kDisablePopupBlocking[]          = "disable-popup-blocking";
 
-// Disable requests that webkit labels TargetIsPrefetch.  As of
-// writing only <link rel=prefetch...> but also eventually
-// Link: headers.
-const char kDisablePrefetch[]               = "disable-prefetch";
-
 // Normally when the user attempts to navigate to a page that was the result of
 // a post we prompt to make sure they want to. This switch may be used to
 // disable that check. This switch is used during automated testing.
@@ -316,6 +316,11 @@ const char kEnableCloudPrintProxy[]         = "enable-cloud-print-proxy";
 // Enables the Cloud Print dialog hosting code.
 const char kEnableCloudPrint[]              = "enable-cloud-print";
 
+// Enable requests that webkit labels TargetIsPrefetch.  As of
+// writing only <link rel=prefetch...> but also eventually
+// Link: headers.
+const char kEnableContentPrefetch[]         = "enable-content-prefetch";
+
 // Enables the cookie prompt.
 const char kEnableCookiePrompt[]            = "enable-cookie-prompt";
 
@@ -389,11 +394,6 @@ const char kEnableNativeWebWorkers[]        = "enable-native-web-workers";
 // Enable speculative TCP/IP preconnection.
 const char kEnablePreconnect[]              = "enable-preconnect";
 
-// Enable requests that webkit labels TargetIsPrefetch.  As of
-// writing only <link rel=prefetch...> but also eventually
-// Link: headers.
-const char kEnablePrefetch[]               = "enable-prefetch";
-
 // Enable caching of pre-parsed JS script data.  See http://crbug.com/32407.
 const char kEnablePreparsedJsCaching[]      = "enable-preparsed-js-caching";
 
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 0db5f99..00385c3 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -51,6 +51,7 @@ extern const char kDisableAudio[];
 extern const char kDisableAuthNegotiateCnameLookup[];
 extern const char kDisableBackingStoreLimit[];
 extern const char kDisableByteRangeSupport[];
+extern const char kDisableContentPrefetch[];
 extern const char kDisableCustomJumpList[];
 extern const char kDisableDatabases[];
 extern const char kDisableDesktopNotifications[];
@@ -61,7 +62,6 @@ extern const char kDisableGeolocation[];
 extern const char kDisableHangMonitor[];
 extern const char kDisableInternalFlash[];
 extern const char kDisableIPv6[];
-extern const char kDisablePreconnect[];
 extern const char kDisableJavaScript[];
 extern const char kDisableJava[];
 extern const char kDisableLocalStorage[];
@@ -70,6 +70,7 @@ extern const char kDisableNewTabFirstRun[];
 extern const char kDisableOutdatedPlugins[];
 extern const char kDisablePlugins[];
 extern const char kDisablePopupBlocking[];
+extern const char kDisablePreconnect[];
 extern const char kDisablePromptOnRepost[];
 extern const char kDisableRemoteFonts[];
 extern const char kDisableRendererAccessibility[];
@@ -104,6 +105,7 @@ extern const char kEnableRemoting[];
 extern const char kEnableClickToPlay[];
 extern const char kEnableCloudPrintProxy[];
 extern const char kEnableCloudPrint[];
+extern const char kEnableContentPrefetch[];
 extern const char kEnableCookiePrompt[];
 extern const char kEnableDeviceMotion[];
 extern const char kEnableDeviceOrientation[];
@@ -125,7 +127,6 @@ extern const char kEnableMonitorProfile[];
 extern const char kEnableNaCl[];
 extern const char kEnableNativeWebWorkers[];
 extern const char kEnablePreconnect[];
-extern const char kEnablePrefetch[];
 extern const char kEnablePreparsedJsCaching[];
 extern const char kEnablePrintPreview[];
 extern const char kEnableSearchProviderApiV2[];