Added a WebRTC HD measurement.

This test measures CPU and memory when we acquire a HD stream with
WebRTC. The existing local-video.html demo will acquire whatever is the
default, which currently is VGA.

The demo page is taken from our GitHub demo repository and is only
lightly edited to get js paths right.

BUG=413577

Review URL: https://codereview.chromium.org/551863005

Cr-Commit-Position: refs/heads/master@{#296700}

tools/perf/page_sets/data/webrtc_cases.json

+{
+    "description": "Describes the Web Page Replay archives for a page set. Don't edit by hand! Use record_wpr for updating.", 
+    "archives": {
+        "webrtc_cases_000.wpr": [
+            "third_party/webrtc/samples/js/demos/html/pc1.html", 
+            "webrtc/local-video.html", 
+            "http://googlechrome.github.io/webrtc/samples/web/content/getusermedia-resolution/"
+        ]
+    }
+}
\ No newline at end of file

tools/perf/page_sets/data/webrtc_cases_000.wpr.sha1

+2aa61e6431e7c4f380b7980a8d0b8e7d8c401f18
\ No newline at end of file

tools/perf/page_sets/webrtc_cases.py

@@ -35,19 +35,26 @@ class Page2(WebrtcCasesPage):
       url='file://third_party/webrtc/samples/js/demos/html/pc1.html',
       page_set=page_set)
 
-  def RunEndure(self, action_runner):
+  def RunWebrtc(self, action_runner):
     action_runner.ClickElement('button[id="btn1"]')
     action_runner.Wait(2)
     action_runner.ClickElement('button[id="btn2"]')
     action_runner.Wait(10)
     action_runner.ClickElement('button[id="btn3"]')
 
+class Page3(WebrtcCasesPage):
+
+  """ Why: Acquires a high definition local stream. """
+
+  def __init__(self, page_set):
+    super(Page3, self).__init__(
+      url=('http://googlechrome.github.io/webrtc/samples/web/content/'
+           'getusermedia-resolution/'),
+      page_set=page_set)
+
   def RunWebrtc(self, action_runner):
-    action_runner.ClickElement('button[id="btn1"]')
-    action_runner.Wait(2)
-    action_runner.ClickElement('button[id="btn2"]')
+    action_runner.ClickElement('button[id="hd"]')
     action_runner.Wait(10)
-    action_runner.ClickElement('button[id="btn3"]')
 
 
 class WebrtcCasesPageSet(page_set_module.PageSet):
@@ -56,7 +63,10 @@ class WebrtcCasesPageSet(page_set_module.PageSet):
 
   def __init__(self):
     super(WebrtcCasesPageSet, self).__init__(
+      archive_data_file='data/webrtc_cases.json',
+      bucket=page_set_module.PUBLIC_BUCKET,
       serving_dirs=['third_party/webrtc/samples/js'])
 
     self.AddPage(Page1(self))
     self.AddPage(Page2(self))
+    self.AddPage(Page3(self))