Added "controlled by" indicators for mouselock and ppapi broker.

These settings were originally not manageable by extensions (or other means), and therefore had no such indicators.

Screenshots are attached to the linked bug.

BUG=459141

Review URL: https://codereview.chromium.org/928373002

Cr-Commit-Position: refs/heads/master@{#316568}

chrome/browser/resources/options/content_settings.html

@@ -386,19 +386,31 @@ <h3 i18n-content="mouselockTabLabel"></h3>
         <div class="radio">
           <label>
             <input type="radio" name="mouselock" value="allow">
-            <span i18n-content="mouselockAllow"></span>
+            <span>
+              <span i18n-content="mouselockAllow"></span>
+              <span class="controlled-setting-indicator"
+                  content-setting="mouselock" value="allow"></span>
+            </span>
           </label>
         </div>
         <div class="radio">
           <label>
             <input type="radio" name="mouselock" value="ask">
-            <span i18n-content="mouselockAsk"></span>
+            <span>
+              <span i18n-content="mouselockAsk"></span>
+              <span class="controlled-setting-indicator"
+                  content-setting="mouselock" value="ask"></span>
+            </span>
           </label>
         </div>
         <div class="radio">
           <label>
             <input type="radio" name="mouselock" value="block">
-            <span i18n-content="mouselockBlock"></span>
+            <span>
+              <span i18n-content="mouselockBlock"></span>
+              <span class="controlled-setting-indicator"
+                  content-setting="mouselock" value="block"></span>
+            </span>
           </label>
         </div>
         <div class="settings-row">
@@ -499,19 +511,31 @@ <h3 i18n-content="ppapiBrokerTabLabel"></h3>
         <div class="radio">
           <label>
             <input type="radio" name="ppapi-broker" value="allow">
-            <span i18n-content="ppapiBrokerAllow"></span>
+            <span>
+              <span i18n-content="ppapiBrokerAllow"></span>
+              <span class="controlled-setting-indicator"
+                  content-setting="ppapi-broker" value="allow"></span>
+            </span>
           </label>
         </div>
         <div class="radio">
           <label>
             <input type="radio" name="ppapi-broker" value="ask">
-            <span i18n-content="ppapiBrokerAsk"></span>
+            <span>
+              <span i18n-content="ppapiBrokerAsk"></span>
+              <span class="controlled-setting-indicator"
+                  content-setting="ppapi-broker" value="ask"></span>
+            </span>
           </label>
         </div>
         <div class="radio">
           <label>
             <input type="radio" name="ppapi-broker" value="block">
-            <span i18n-content="ppapiBrokerBlock"></span>
+            <span>
+              <span i18n-content="ppapiBrokerBlock"></span>
+              <span class="controlled-setting-indicator"
+                  content-setting="ppapi-broker" value="block"></span>
+            </span>
           </label>
         </div>
         <div class="settings-row">