Collect UMA statistics on which chrome://flags lead to chrome restart on ChromeOS.

chrome/browser/chromeos/login/report_custom_flags.cc

Index: chrome/browser/chromeos/login/report_custom_flags.cc
diff --git a/chrome/browser/chromeos/login/report_custom_flags.cc b/chrome/browser/chromeos/login/report_custom_flags.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2e1ea919997f328846bb7142c50ce57c1506ec05
--- /dev/null
+++ b/chrome/browser/chromeos/login/report_custom_flags.cc
@@ -0,0 +1,333 @@
+// Copyright 2014 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/chromeos/login/report_custom_flags.h"
+
+#include <algorithm>
+#include <set>
+#include <string>
+
+#include "ash/ash_switches.h"
+#include "base/logging.h"
+#include "base/metrics/sparse_histogram.h"
+#include "cc/base/switches.h"
+#include "chrome/common/chrome_switches.h"
+#include "chromeos/chromeos_switches.h"
+#include "components/autofill/core/common/autofill_switches.h"
+#include "components/cloud_devices/common/cloud_devices_switches.h"
+#include "components/data_reduction_proxy/common/data_reduction_proxy_switches.h"
+#include "components/nacl/common/nacl_switches.h"
+#include "components/password_manager/core/common/password_manager_switches.h"
+#include "content/public/common/content_switches.h"
+#include "extensions/common/switches.h"
+#include "third_party/cros_system_api/switches/chrome_switches.h"
+#include "ui/app_list/app_list_switches.h"
+#include "ui/base/ui_base_switches.h"
+#include "ui/display/display_switches.h"
+#include "ui/events/event_switches.h"
+#include "ui/gfx/switches.h"
+#include "ui/keyboard/keyboard_switches.h"
+#include "ui/native_theme/native_theme_switches.h"
+#include "ui/views/views_switches.h"
+
+namespace {
+
+/* Reserved histogram values */
+enum {
+  UNKNOWN_FLAG = 0,
+  BAD_FLAG_FORMAT = 1,
+};
+
+/* This table shoud consist of all possible command-line switches from
+  chrome/browser/about_flags.cc
+
+  This is a mapping between switch name and UMA id. Indexes in this table

[sky, 2014/06/25 16:14:36]

Hm, I would expect a mapping to have two values, this is actually a list.

+  must never be modified. Plase add new value to the end of the table only!
+
+  If some entry should be deleted, replace it with empty string and a comment
+  describing what was deleted.
+
+  This table must be in sync with LoginCustomFlags in
+  tools/metrics/histogram.xml .

[sky, 2014/06/25 16:14:36]

I think you mean tools/metrics/histograms/histograms.xml.

+
+  NOTE: This table is intentionally unsorted to force anyone to read this

[sky, 2014/06/25 16:14:36]

If only it were that easy.

+  comment before modifying the table.
+*/
+
+const char* const chrome_custom_histogram_switches[] = {
+    "" /* UNKNOWN_FLAG - reserved */,
+    "" /* BAD_FLAG_FORMAT - reserved */,
+    "" /* unused - reserved */,
+    "" /* unused - reserved */,
+    "" /* unused - reserved */,
+    switches::kOverscrollHistoryNavigation,
+    switches::kEnableServiceWorkerSync,
+    switches::kNoPings,
+    switches::kNoExperiments,
+    switches::kEnableOneCopy,
+    switches::kDisableGestureTapHighlight,
+    chromeos::switches::kFileManagerEnableNewGallery,
+    switches::kEnableQuicHttps,
+    chromeos::switches::kEnableNetworkPortalNotification,
+    switches::kEnableCompositingForFixedPosition,
+    keyboard::switches::kEnableVirtualKeyboardOverscroll,
+    switches::kAllowInsecureWebSocketFromHttpsOrigin,
+    switches::kEnableWebBasedSignin,
+    cc::switches::kShowFPSCounter,
+    switches::kEnableOfflineAutoReload,
+    chromeos::switches::kEnableFileManagerMTP,
+    switches::kEnablePanels,
+    extensions::switches::kEnableScriptsRequireAction,
+    switches::kEnableSmoothScrolling,
+    switches::kDisableDelegatedRenderer,
+    switches::kTouchEventsDisabled,
+    switches::kMalwareInterstitialVersionV2,
+    switches::kDisableTouchEditing,
+    switches::kPrefetchSearchResults,
+    switches::kDisablePasswordManagerReauthentication,
+    switches::kEnableSearchButtonInOmniboxAlways,
+    switches::kDisableWebAudio,
+    switches::kDefaultTileHeight,
+    switches::kEnableSessionCrashedBubble,
+    chromeos::switches::kDisableQuickofficeComponentApp,
+    switches::kDebugPackedApps,
+    switches::kEnableSuggestionsService,
+    switches::kTabCaptureDownscaleQuality,
+    switches::kManualEnhancedBookmarksOptout,
+    switches::kDisableAcceleratedFixedRootBackground,
+    ash::switches::kAshTouchHud,
+    switches::kDisableDeviceEnumeration,
+    cc::switches::kDisablePinchVirtualViewport,
+    switches::kEnableDeferredImageDecoding,
+    keyboard::switches::kDisableInputView,
+    switches::kDisableDeviceDiscoveryNotifications,
+    autofill::switches::kEnablePasswordGeneration,
+    switches::kManualEnhancedBookmarks,
+    extensions::switches::kExtensionContentVerification,
+    switches::kEnableEphemeralApps,
+    switches::kEnableQuic,
+    chromeos::switches::kEnableFirstRunUITransitions,
+    switches::kEnableSearchButtonInOmniboxForStr,
+    switches::kEnableDistanceFieldText,
+    switches::kDisableTextInputFocusManager,
+    switches::kTouchScrollingMode,
+    switches::kDisableOverlayScrollbar,
+    cc::switches::kMaxTilesForInterestArea,
+    switches::kForceGpuRasterization,
+    switches::kAllowNaClSocketAPI,
+    chromeos::switches::kEnableRequestTabletSite,
+    extensions::switches::kExtensionContentVerificationEnforceStrict,
+    switches::kDisableSoftwareRasterizer,
+    switches::kEnableAppsFileAssociations,
+    switches::kSSLInterstitialVersionV2Gray,
+    autofill::switches::kShowAutofillTypePredictions,
+    switches::kEnableViewportMeta,
+    switches::kSilentDebuggerExtensionAPI,
+    switches::kDisableGpuRasterization,
+    switches::kFlagSwitchesBegin,
+    switches::kDisableOfflineLoadStaleCache,
+    keyboard::switches::kEnableVirtualKeyboard,
+    switches::kDisableThreadedCompositing,
+    switches::kEnableGpuRasterization,
+    switches::kDisableSettingsWindow,
+    switches::kEnableDelegatedRenderer,
+    switches::kEnableScrollPrediction,
+    switches::kEnableAcceleratedOverflowScroll,
+    switches::kDisableCompositingForFixedPosition,
+    switches::kDisableWebRtcHWEncoding,
+    switches::kEnableSearchButtonInOmniboxForStrOrIip,
+    switches::kEnableBleedingEdgeRenderingFastPaths,
+    switches::kDisableSavePasswordBubble,
+    switches::kEnableSettingsWindow,
+    switches::kDisableDeviceDiscovery,
+    switches::kDisableZeroCopy,
+    switches::kEnableNaClDebug,
+    switches::kEnableSavePasswordBubble,
+    switches::kDisablePrefixedEncryptedMedia,
+    switches::kDefaultTileWidth,
+    switches::kDisableEmbeddedSharedWorker,
+    switches::kDisableSessionCrashedBubble,
+    switches::kEnableDeviceDiscoveryNotifications,
+    chromeos::switches::kEnableCarrierSwitching,
+    switches::kEnableOfflineLoadStaleCache,
+    switches::kEnableAnswersInSuggest,
+    switches::kEnableAppList,
+    cc::switches::kEnablePinchVirtualViewport,
+    switches::kDisableOfflineAutoReload,
+    switches::kEnableFastTextAutosizing,
+    switches::kEnablePrintPreviewRegisterPromos,
+    switches::kEnableThreadedCompositing,
+    switches::kEnablePermissionsBubbles,
+    switches::kEnableEasyUnlock,
+    chromeos::switches::kDisableSamlSignin,
+    autofill::switches::kDisableIgnoreAutocompleteOff,
+    views::switches::kDisableViewsRectBasedTargeting,
+    switches::kPerformanceMonitorGathering,
+    cc::switches::kShowCompositedLayerBorders,
+    keyboard::switches::kEnableInputView,
+    autofill::switches::kWalletServiceUseSandbox,
+    chromeos::switches::kPolicySwitchesBegin,
+    switches::kEnableOverlayScrollbar,
+    switches::kEnableAccountConsistency,
+    switches::kDisableMediaSource,
+    switches::kEnableServiceWorker,
+    switches::kEnableTouchEditing,
+    switches::kEnableTranslateNewUX,
+    switches::kForceDeviceScaleFactor,
+    ash::switches::kAshDebugShortcuts,
+    switches::kDisableAccelerated2dCanvas,
+    switches::kDisableSuggestionsService,
+    switches::kNumRasterThreads,
+    password_manager::switches::kEnableAutomaticPasswordSaving,
+    switches::kEnableAppWindowControls,
+    switches::kDisableQuic,
+    switches::kDisableOriginChip,
+    switches::kMalwareInterstitialVersionV3,
+    switches::kTouchEvents,
+    keyboard::switches::kEnableExperimentalInputViewFeatures,
+    keyboard::switches::kDisableVirtualKeyboardOverscroll,
+    switches::kEnableAsyncDns,
+    switches::kGoogleProfileInfo,
+    switches::kEnableExperimentalWebPlatformFeatures,
+    switches::kEnableSpellingAutoCorrect,
+    switches::kEnableWebMIDI,
+    switches::kEnableNaCl,
+    switches::kOutOfProcessPdf,
+    switches::kDisableTouchAdjustment,
+    switches::kEnableProminentURLAppFlow,
+    switches::kEnableHarfBuzzRenderText,
+    switches::kEnableOriginChipAlways,
+    switches::kDisableDistanceFieldText,
+    switches::kEnableTextInputFocusManager,
+    switches::kFastUserSwitching,
+    switches::kEnableEncryptedMedia,
+    switches::kDisableQuicHttps,
+    switches::kSSLInterstitialVersionV1,
+    switches::kEnableSpdy4,
+    switches::kDisablePermissionsBubbles,
+    switches::kNewAvatarMenu,
+    switches::kEnableHighDpiCompositingForFixedPosition,
+    switches::kEnableTouchDragDrop,
+    switches::kDisableLCDText,
+    switches::kEnableCompositingForTransition,
+    switches::kEnableImplSidePainting,
+    switches::kIgnoreGpuBlacklist,
+    switches::kTouchEventsEnabled,
+    switches::kEnableDownloadResumption,
+    switches::kJavaScriptFlags,
+    switches::kDisableCompositingForTransition,
+    switches::kTouchScrollingModeSyncTouchmove,
+    extensions::switches::kEnableExperimentalExtensionApis,
+    switches::kEnableGestureTapHighlight,
+    switches::kNaClDebugMask,
+    switches::kEnhancedBookmarksExperiment,
+    switches::kEnableFastUnload,
+    chromeos::switches::kDisableBootAnimation,
+    switches::kDisableNTPOtherSessionsMenu,
+    switches::kEnableOriginChipOnSrp,
+    switches::kDisableAccountConsistency,
+    switches::kScrollEndEffect,
+    switches::kTouchScrollingModeTouchcancel,
+    switches::kDisablePnacl,
+    switches::kSSLInterstitialVersionV2Colorful,
+    switches::kEnableNewProfileManagement,
+    switches::kEnableAppsShowOnFirstPaint,
+    switches::kEnablePinch,
+    switches::kResetAppListInstallState,
+    switches::kDisableImplSidePainting,
+    autofill::switches::kDisablePasswordGeneration,
+    switches::kEnableExperimentalCanvasFeatures,
+    switches::kEnableOfflineAutoReloadVisibleOnly,
+    switches::kEnableStreamlinedHostedApps,
+    switches::kTouchScrollingModeAsyncTouchmove,
+    switches::kDisableTouchDragDrop,
+    data_reduction_proxy::switches::kEnableDataReductionProxyDev,
+    switches::kEnableSpellingFeedbackFieldTrial,
+    switches::kTabCaptureUpscaleQuality,
+    switches::kEnableLCDText,
+    keyboard::switches::kEnableSwipeSelection,
+    switches::kEnableWebGLDraftExtensions,
+    switches::kEnableSyncSyncedNotifications,
+    switches::kEnableCloudDevices,
+    extensions::switches::kExtensionContentVerificationBootstrap,
+    switches::kFlagSwitchesEnd,
+    switches::kDisableSearchButtonInOmnibox,
+    switches::kDisableOfflineAutoReloadVisibleOnly,
+    chromeos::switches::kPolicySwitchesEnd,
+    switches::kDisableExperimentalWebGL,
+    extensions::switches::kExtensionContentVerificationEnforce,
+    switches::kDisableLayerSquashing,
+    extensions::switches::kExtensionsOnChromeURLs,
+    chromeos::switches::kDisableNetworkPortalNotification,
+    ash::switches::kAshEnableTouchViewTesting,
+    chromeos::switches::kEnableTouchpadThreeFingerClick,
+    chromeos::switches::kFileManagerEnableNewAudioPlayer,
+    switches::kDisableFastTextAutosizing,
+    switches::kDisableMinimizeOnSecondLauncherItemClick,
+    switches::kDisableWebRtcHWDecoding,
+    switches::kDisableAcceleratedVideoDecode,
+    switches::kSavePageAsMHTML,
+    switches::kDisableNewProfileManagement,
+    switches::kEnableZeroCopy,
+    switches::kEnableLinkableEphemeralApps,
+    switches::kUseSimpleCacheBackend,
+    switches::kEnableDevToolsExperiments,
+    switches::kDisableSyncSyncedNotifications,
+    cc::switches::kDisableCompositorTouchHitTesting,
+    switches::kEnableAcceleratedFixedRootBackground,
+    switches::kEnableTcpFastOpen,
+    switches::kDisableAsyncDns,
+    switches::kSyncfsEnableDirectoryOperation,
+    data_reduction_proxy::switches::kDisableDataReductionProxyDev,
+    ui::switches::kDisableDisplayColorCalibration,
+    switches::kDisableAcceleratedOverflowScroll,
+
+    /* Insert new entries here. Never modify existing entries! */
+};
+
+}  // namespace
+
+namespace chromeos {
+
+void ReportCustomFlags(const std::set<std::string>& command_line_difference) {
+  for (std::set<std::string>::const_iterator i =
+           command_line_difference.begin();
+       i != command_line_difference.end();
+       ++i) {
+    int uma_id = UNKNOWN_FLAG;
+    if (i->size() > 2) {
+      // skip '--' before switch name
+      const char* switch_name = &((*i)[2]);
+      const char* const* end = chrome_custom_histogram_switches +
+                               arraysize(chrome_custom_histogram_switches);
+      const char* const* histflag = std::find_if(
+          chrome_custom_histogram_switches,
+          end,
+          std::not1(std::bind1st(std::ptr_fun(strcmp), switch_name)));
+      uma_id = histflag - chrome_custom_histogram_switches;
+      if (histflag == end) {
+        uma_id = UNKNOWN_FLAG;
+        LOG(ERROR) << "ReportCustomFlags(): flag '" << *i << "' ('"
+                   << switch_name << "') is unknown.";
+      }
+    } else {
+      uma_id = BAD_FLAG_FORMAT;
+      LOG(ERROR) << "ReportCustomFlags(): flag '" << *i
+                 << "' has incorrect format.";
+    }
+    DCHECK_LT(uma_id,
+              static_cast<int>(arraysize(chrome_custom_histogram_switches)));
+    VLOG(1) << "ReportCustomFlags(): '" << *i << "', uma_id=" << uma_id << " ('"
+            << chrome_custom_histogram_switches[uma_id] << "')";
+    UMA_HISTOGRAM_SPARSE_SLOWLY("Login.CustomFlags", uma_id);
+  }
+}
+
+const char* const* GetChromeCustomHistogramSwitchesForTesting(
+    size_t* out_size) {
+  *out_size = arraysize(chrome_custom_histogram_switches);
+  return chrome_custom_histogram_switches;
+}
+
+}  // namespace chromeos