Remove Finch config control for contextual search.

ios/chrome/browser/ui/contextual_search/touch_to_search_permissions_mediator.mm

Index: ios/chrome/browser/ui/contextual_search/touch_to_search_permissions_mediator.mm
diff --git a/ios/chrome/browser/ui/contextual_search/touch_to_search_permissions_mediator.mm b/ios/chrome/browser/ui/contextual_search/touch_to_search_permissions_mediator.mm
index 741970b05ccca6b876f704cc64a90bd764a4492b..ce48928e87d6e4f2240e1c138de329cf95c1e112 100644
--- a/ios/chrome/browser/ui/contextual_search/touch_to_search_permissions_mediator.mm
+++ b/ios/chrome/browser/ui/contextual_search/touch_to_search_permissions_mediator.mm
@@ -9,7 +9,6 @@
 #include "base/command_line.h"
 #import "base/ios/weak_nsobject.h"
 #include "base/logging.h"
-#include "base/metrics/field_trial.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "components/prefs/pref_service.h"
 #include "components/search_engines/template_url_service.h"
@@ -24,9 +23,6 @@
 #include "net/base/network_change_notifier.h"
 
 namespace {
-// Field trial constants.
-const char kContextualSearchFieldTrialName[] = "ContextualSearchIOS";
-const char kContextualSearchFieldTrialEnabled[] = "Enabled";
 // Maps pref string values to state enum.
 const struct {
   const char* value;
@@ -68,22 +64,25 @@ const struct {
 @synthesize observing = _observing;
 
 + (BOOL)isTouchToSearchAvailableOnDevice {
-  // If the disable flag is flipped, the feature isn't available.
-  // If the enable flag is flipped, it's available.
-  // If the browser is in the field trial, it's available.
-  BOOL available = NO;
+  // By default the feature is not available. If the enable flag
+  // (switches::kEnableContextualSearch) is flipped, then it is available.
+  // The disable switch (switches::kDisableContextualSearch) is also supported,
+  // although it is only useful when Finch experiments are also supported.
+
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableContextualSearch)) {
+    // If both enable and disable flags are present, disable wins.

[lindsayw, 2017/01/10 19:08:53]

Ah, took me a minute to understand you're not actually evaluating both here, but
rather just saying if disable is true, then no matter what enable is set to then
always default to disabled.

     return NO;
-  } else if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-                 switches::kEnableContextualSearch)) {
-    available = YES;
-  } else {
-    available =
-        base::FieldTrialList::FindFullName(kContextualSearchFieldTrialName) ==
-        kContextualSearchFieldTrialEnabled;
   }
-  return available && !tests_hook::DisableContextualSearch();
+
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableContextualSearch)) {
+    // Even if the command line flag is flipped, don't enable the feature if
+    // test hooks disable it.
+    return !tests_hook::DisableContextualSearch();
+  }
+
+  return NO;
 }
 
 - (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState {