Add a mechanism to force parameters of a group to a specific value.

content/public/common/content_switches.cc

 // Copyright (c) 2012 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 "content/public/common/content_switches.h"
 
 namespace switches {
 
 // The number of MSAA samples for canvas2D. Requires MSAA support by GPU to
 // have an effect. 0 disables MSAA.
@@ skipping 511 matching lines @@
 // This option can be used to force field trials when testing changes locally.
 // The argument is a list of name and value pairs, separated by slashes. If a
 // trial name is prefixed with an asterisk, that trial will start activated.
 // For example, the following argument defines two trials, with the second one
 // activated: "GoogleNow/Enable/*MaterialDesignNTP/Default/"
 // This option is also used by the browser to send the list of trials to
 // renderers, using the same format. See
 // FieldTrialList::CreateTrialsFromString() in field_trial.h for details.
 const char kForceFieldTrials[]              = "force-fieldtrials";
 
+// This option can be used to force parameters of field trials when testing
+// changes locally. The argument is a list of key/value pairs prefixed by
+// Trial/Group pair. The following shows setting parameters to 2 experiments
+// where in the first, it forces "id" to be "foo" for the "Enabled" group of
+// the "EnhancedBookmarks" trial:
+// "EnhancedBookmarks.Enabled:id/foo,Experiment2.Group1:key1/value1"
+// See variations::AssociateParamsFromString() in variations_associated_data.h
+// for details.
+const char kForceFieldTrialParams[]        = "force-fieldtrial-params";
+
 // Always use the Skia GPU backend for drawing layer tiles. Only valid with GPU
 // accelerated compositing + impl-side painting. Overrides the
 // kEnableGpuRasterization flag.
 const char kForceGpuRasterization[]        = "force-gpu-rasterization";
 
 // The number of multisample antialiasing samples for GPU rasterization.
 // Requires MSAA support on GPU to have an effect. 0 disables MSAA.
 const char kGpuRasterizationMSAASampleCount[] =
     "gpu-rasterization-msaa-sample-count";
 
@@ skipping 454 matching lines @@
 // Windows Vista and later.
 const char kTraceExportEventsToETW[] = "trace-export-events-to-etw";
 #endif
 
 // Enables the use of NPAPI plugins.
 const char kEnableNpapi[]                   = "enable-npapi";
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches