Fix for Multipage selection by dragging mouse in OOP case in PDF.

chrome/browser/resources/pdf/pdf.js

Index: chrome/browser/resources/pdf/pdf.js
diff --git a/chrome/browser/resources/pdf/pdf.js b/chrome/browser/resources/pdf/pdf.js
index 9123627f884ba66f0a30883269619f4c3e9d8b41..755025d9bda7b04f0c83add2c640575376dcf66f 100644
--- a/chrome/browser/resources/pdf/pdf.js
+++ b/chrome/browser/resources/pdf/pdf.js
@@ -58,6 +58,19 @@ function onNavigateInNewTab(url) {
 PDFViewer.MIN_TOOLBAR_OFFSET = 15;
 
 /**
+ * The timer interval for drag scroll when we have selection and mouse is

[Sam McNally, 2015/02/06 03:43:06]

The period of time to wait between updating the viewport position by the scroll
velocity.

[Deepak, 2015/02/06 08:33:42]

Done.

+ * dragged out of the viewport. The callback function will get called after
+ * this interval till timer get cleared.
+ */
+PDFViewer.DRAG_TIMER_INTERVAL = 100;
+
+/**
+ * The maximum scroll velocity when we have selection and drag mouse out of

[Sam McNally, 2015/02/06 03:43:07]

The maximum drag scroll velocity.

[Deepak, 2015/02/06 08:33:43]

Done.

+ * viewport.
+ */
+PDFViewer.MAX_SCROLL_VELOCITY = 100;
+
+/**
  * Creates a new PDFViewer. There should only be one of these objects per
  * document.
  * @constructor
@@ -193,6 +206,9 @@ function PDFViewer(streamDetails) {
   this.navigator_ = new Navigator(this.streamDetails_.originalUrl,
       this.viewport_, this.paramsParser_, onNavigateInCurrentTab,
       onNavigateInNewTab);
+  this.mousemoveCallback_ = null;
+  this.timerId_ = null;
+  this.scrollVelocity_ = null;
 }
 
 PDFViewer.prototype = {
@@ -519,7 +535,106 @@ PDFViewer.prototype = {
         if (this.isMaterial_)
           this.bookmarksPane.bookmarks = message.data.bookmarks;
         break;
+      case 'setIsSelecting':
+        if (message.data.isSelecting && !this.mousemoveCallback_) {
+          this.mousemoveCallback_ = this.selectionDragListener_.bind(this);

[Sam McNally, 2015/02/06 03:43:07]

I meant only do this once and then reuse the same callback in the future.

[Deepak, 2015/02/06 08:33:43]

Done.

+          this.plugin_.addEventListener('mousemove',

[Sam McNally, 2015/02/06 03:43:07]

Break after the (.

[Deepak, 2015/02/06 08:33:43]

ok, I will run clang format for this.

+              this.mousemoveCallback_, false);
+        } else {
+          this.clearTimerInterval_();
+          if (this.mousemoveCallback_) {
+            this.plugin_.removeEventListener('mousemove',

[Sam McNally, 2015/02/06 03:43:07]

Ditto.

[Deepak, 2015/02/06 08:33:43]

Done.

+                this.mousemoveCallback_, false);
+            this.mousemoveCallback_ = null;

[Sam McNally, 2015/02/06 03:43:07]

Delete.

[Deepak, 2015/02/06 08:33:43]

Done.

+          }
+        }
+        break;
+    }
+  },
+
+  /**
+   * @private
+   * Start the timer to call dragScrollPage_ function at regular interval till

[Sam McNally, 2015/02/06 03:43:07]

until the timer is stopped.

[Deepak, 2015/02/06 08:33:43]

Done.

+   * timer get cleared.
+   */
+  setTimerInterval_: function() {

[Sam McNally, 2015/02/06 03:43:07]

startDragScrollTimer_

[Deepak, 2015/02/06 08:33:43]

Done.

+    this.timerId_ =
+        window.setInterval(this.dragScrollPage_.bind(this),
+        PDFViewer.DRAG_TIMER_INTERVAL);
+  },
+
+  /**
+   * @private
+   * Clear the timer if it is active and reset timerId_.

[Sam McNally, 2015/02/06 03:43:06]

Stops the drag scroll timer if it is active.

[Deepak, 2015/02/06 08:33:43]

Done.

+   */
+  clearTimerInterval_: function() {

[Sam McNally, 2015/02/06 03:43:07]

stopDragScrollTimer_

[Deepak, 2015/02/06 08:33:43]

Done.

+    if (this.timerId_ !== null) {
+      window.clearInterval(this.timerId_);
+      this.timerId_ = null;
+    }
+  },
+
+  /**
+   * @private
+   * Handles scrolling in the page when we drag mouse out of the viewport and

[Sam McNally, 2015/02/06 03:43:07]

Scrolls the viewport by the current scroll velocity.

[Deepak, 2015/02/06 08:33:43]

Done.

+   * does not get mousemove event.
+   */
+  dragScrollPage_: function() {
+    var position = this.viewport_.position;
+    position.y += this.scrollVelocity_.y;
+    position.x += this.scrollVelocity_.x;
+    this.viewport_.position = position;
+  },
+
+  /**
+   * @private
+   * Calculate velocity of scroll in the x and y direction when we drag mouse

[Sam McNally, 2015/02/06 03:43:07]

Calculate the velocity to scroll while dragging using the distance of the cursor
outside the viewport.

[Deepak, 2015/02/06 08:33:43]

Done.

+   * out of the viewport and does not move mouse. The scroll velocity depends
+   * upon mouse pointer distance from the viewport.
+   * @return {Object} Object with x and y direction scroll velocity.
+   */
+  calculateVelocity_: function(event) {
+    var x = Math.min(Math.max(-event.offsetX, event.offsetX -

[Sam McNally, 2015/02/06 03:43:07]

Please clang-format this.

[Deepak, 2015/02/06 08:33:43]

Done.

+        this.plugin_.offsetWidth, 0), PDFViewer.MAX_SCROLL_VELOCITY) *
+        Math.sign(event.offsetX);
+    var y = Math.min(Math.max(-event.offsetY, event.offsetY -
+        this.plugin_.offsetHeight, 0), PDFViewer.MAX_SCROLL_VELOCITY) *
+        Math.sign(event.offsetY);
+    return {x: x, y: y};
+  },
+
+  /**
+   * @private
+   * Handles mousemove events. Scrolls page when mouse move happen reacting to

[Sam McNally, 2015/02/06 03:43:07]

This doesn't do any scrolling itself. It just updates the velocity and maybe
starts or stops the timer.

[Deepak, 2015/02/06 08:33:43]

Done.

+   * the direction of scroll. When mouse move event does not come then we are
+   * scrolling based on timer.
+   * @param {Object} event The mousemove event.
+   */
+  selectionDragListener_: function(event) {
+    var position = this.viewport_.position;

[Sam McNally, 2015/02/06 03:43:06]

These bounds checks aren't necessary. Remove them.

[Deepak, 2015/02/06 08:33:42]

Done.

+    var viewportRect = {
+      x1: position.x / this.viewport_.zoom,
+      y1: position.y / this.viewport_.zoom,
+      x2: (position.x + this.viewport_.size.width) / this.viewport_.zoom,
+      y2: (position.y + this.viewport_.size.height) / this.viewport_.zoom
+    };
+    var point = {
+      x: event.pageX / this.viewport_.zoom,
+      y: event.pageY / this.viewport_.zoom
+    };
+
+    if ((point.x >= viewportRect.x1 && point.x <= viewportRect.x2) &&
+        (point.y >= viewportRect.y1 && point.y <= viewportRect.y2)) {
+      this.clearTimerInterval_();
+      return;
+    }
+    this.scrollVelocity_ = this.calculateVelocity_(event);
+    if ((this.scrollVelocity_.x != 0 || this.scrollVelocity_.y != 0) &&
+        !this.timerId_) {
+      this.setTimerInterval_();

[Sam McNally, 2015/02/06 03:43:07]

Please make setTimerInterval_ idempotent and simplify these ifs to a single
if/else using the velocity.

[Deepak, 2015/02/06 08:33:43]

Done.

     }
+    if (!this.scrollVelocity_.x && !this.scrollVelocity_.y)
+      this.clearTimerInterval_();
   },

[raymes, 2015/02/06 03:11:07]

Can we move all this stuff into a new class in a separate file (called
ViewportScroller or something). We can pass in the viewport and the plugin and
the window.

[Deepak, 2015/02/06 08:33:43]

ya, sure , I will definitely move this code in separate file.
As this issue is blocker, Is it ok, if do this once I got lgtm for these changes
from Sam.?

 
   /**