base: "implement" seek time detection for iOS/Android and add more stubs.

components/metrics/proto/system_profile.proto

 // 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.
 //
 // Stores information about the user's brower and system configuration.
 // The system configuration fields are recorded once per client session.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
@@ skipping 237 matching lines @@
     message TouchScreen {
       // Touch screen vendor id.
       optional uint32 vendor_id = 1;
       // Touch screen product id.
       optional uint32 product_id = 2;
     }
     // Lists vendor and product ids of external touchscreens.
     // Logged on ChromeOS only.
     repeated TouchScreen external_touchscreen = 15;
 
-    // Drive messages are logged on Windows 7+ only for now.
+    // Drive messages are currently logged on Windows 7+, iOS, and Android.
     message Drive {
       // Whether this drive incurs a time penalty when randomly accessed. This
       // should be true for spinning disks but false for SSDs or other
       // flash-based drives.
       optional bool has_seek_penalty = 1;
     }
     // The drive that the application executable was loaded from.
     optional Drive app_drive = 16;
     // The drive that the current user data directory was loaded from.
     optional Drive user_data_drive = 17;
@@ skipping 458 matching lines @@
   // then HAS_OFFSTORE is reported. This should be kept in sync with the
   // corresponding enum in chrome/browser/metrics/extensions_metrics_provider.cc
   enum ExtensionsState {
     NO_EXTENSIONS = 0;
     NO_OFFSTORE_VERIFIED = 1;
     NO_OFFSTORE_UNVERIFIED = 2;
     HAS_OFFSTORE = 3;
   }
   optional ExtensionsState offstore_extensions_state = 19;
 }