From 21efcbdca72b0a9e745ececbb0d9e55e271c49ae Mon Sep 17 00:00:00 2001
From: Erwin Mombay <erwinm@google.com>
Date: Fri, 4 Mar 2016 12:22:18 -0800
Subject: [PATCH] add prerender complete message

---
 src/performance.js                  | 25 +++++++++++++++++++------
 src/service/viewer-impl.js          |  8 ++++++++
 test/functional/test-performance.js | 26 ++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/src/performance.js b/src/performance.js
index fc72a795f975..b4ebb236781f 100644
--- a/src/performance.js
+++ b/src/performance.js
@@ -78,11 +78,8 @@ export class Performance {
     /** @const {!Window} */
     this.win = win;
 
-    /** @const @private {funtion(string,?string=,number=)|undefined} */
-    this.tick_ = undefined;
-
-    /** @const @private {funtion()|undefined} */
-    this.flush_ = undefined;
+    /** @private @const {number} */
+    this.initTime_ = timer.now();
 
     /** @const @private {!Array<TickEventDef>} */
     this.events_ = [];
@@ -137,7 +134,7 @@ export class Performance {
    */
   measureUserPerceivedVisualCompletenessTime_() {
     const didStartInPrerender = !this.viewer_.hasBeenVisible();
-    let docVisibleTime = didStartInPrerender ? -1 : timer.now();
+    let docVisibleTime = didStartInPrerender ? -1 : this.initTime_;
 
     // This is only relevant if the viewer is in prerender mode.
     // (hasn't been visible yet, ever at this point)
@@ -154,11 +151,15 @@ export class Performance {
             : 1 /* MS (magic number for prerender was complete
                    by the time the user opened the page) */;
         this.tickDelta('pc', userPerceivedVisualCompletenesssTime);
+        this.prerenderComplete_(userPerceivedVisualCompletenesssTime);
       } else {
         // If it didnt start in prerender, no need to calculate anything
         // and we just need to tick `pc`. (it will give us the relative
         // time since the viewer initialized the timer)
         this.tick('pc');
+        // We don't have the actual csi timer's clock start time,
+        // so we just have to use `docVisibleTime`.
+        this.prerenderComplete_(timer.now() - docVisibleTime);
       }
       this.flush();
     });
@@ -320,6 +321,18 @@ export class Performance {
       this.setFlushParams_(params);
     });
   }
+
+  /**
+   * @private
+   * @param {number} value
+   */
+  prerenderComplete_(value) {
+    if (this.viewer_ && this.viewer_.isPerformanceTrackingOn()) {
+      this.viewer_.prerenderComplete({
+        'value': value,
+      });
+    }
+  }
 }
 
 
diff --git a/src/service/viewer-impl.js b/src/service/viewer-impl.js
index cc2c2c6845f2..a1c54826ff7e 100644
--- a/src/service/viewer-impl.js
+++ b/src/service/viewer-impl.js
@@ -829,6 +829,14 @@ export class Viewer {
     this.sendMessageUnreliable_('setFlushParams', message, false);
   }
 
+  /**
+   * Triggers "prerenderComplete" event for the viewer.
+   * @param {!JSONObject} message
+   */
+  prerenderComplete(message) {
+    this.sendMessageUnreliable_('prerenderComplete', message, false);
+  }
+
   /**
    * Requests AMP document to receive a message from Viewer.
    * @param {string} eventType
diff --git a/test/functional/test-performance.js b/test/functional/test-performance.js
index 70aaf054c1d2..b051ee9c4989 100644
--- a/test/functional/test-performance.js
+++ b/test/functional/test-performance.js
@@ -308,6 +308,21 @@ describe('performance', () => {
         perf.coreServicesAvailable();
       });
 
+      it('should call prerenderComplete on viewer', () => {
+        clock.tick(100);
+        whenFirstVisibleResolve();
+        const prerenderSpy = sandbox.spy(viewer, 'prerenderComplete');
+        sandbox.stub(viewer, 'isPerformanceTrackingOn').returns(true);
+        return viewer.whenFirstVisible().then(() => {
+          clock.tick(400);
+          whenReadyToRetrieveResourcesResolve();
+          whenViewportLayoutCompleteResolve();
+          return perf.whenViewportLayoutComplete_().then(() => {
+            expect(prerenderSpy.firstCall.args[0].value).to.equal(400);
+          });
+        });
+      });
+
       it('should tick `pc` with opt_value=400 when user request document ' +
          'to be visible before before first viewport completion', () => {
         clock.tick(100);
@@ -352,6 +367,17 @@ describe('performance', () => {
         perf.coreServicesAvailable();
       });
 
+      it('should call prerenderComplete on viewer', () => {
+        const prerenderSpy = sandbox.spy(viewer, 'prerenderComplete');
+        sandbox.stub(viewer, 'isPerformanceTrackingOn').returns(true);
+        clock.tick(300);
+        whenReadyToRetrieveResourcesResolve();
+        whenViewportLayoutCompleteResolve();
+        return perf.whenViewportLayoutComplete_().then(() => {
+          expect(prerenderSpy.firstCall.args[0].value).to.equal(300);
+        });
+      });
+
       it('should tick `pc` with `opt_value=undefined` when user requests ' +
          'document to be visible', () => {
         clock.tick(300);