[turbolizer]: Fix bugs

* The default text (placeholder) in the search box is now present.
* All key events handled by turbolizer are not passed through to Chrome.

Review-Url: https://codereview.chromium.org/2061713002
Cr-Commit-Position: refs/heads/master@{#36936}

tools/turbolizer/graph-view.js

@@ -571,6 +571,7 @@ class GraphView extends View {
     }
 
     var allowRepetition = true;
+    var eventHandled = true; // unless the below switch defaults
     switch(d3.event.keyCode) {
     case 49:
     case 50:
@@ -616,6 +617,12 @@ class GraphView extends View {
       selectNodesThroughEdges(d3.event.keyCode == 38, undefined, true);
       break;
     }
+    default:
+      eventHandled = false;
+      break;
+    }
+    if (eventHandled) {
+      d3.event.preventDefault();
     }
     if (!allowRepetition) {
       state.lastKeyDown = d3.event.keyCode;

tools/turbolizer/index.html

@@ -24,7 +24,8 @@
         <input id="toggle-types" type="image" title="show/hide types"
                src="types.png" alt="show/hide types" class="button-input">
         <input id="search-input" type="text" title="search nodes for regex"
-               alt="search node for regex" class="search-input">
+               alt="search node for regex" class="search-input"
+               placeholder="find with regexp&hellip;">
         <select id="display-selector"></select>
       </span>
       <div id="load-file">