Assigning to owner.

Here is the current state (attached video)

Note : We need to enable the feature from command line as demo mode will not be sufficient for this case.
build/android/adb_chrome_public_command_line "--enable-features=IPH_MediaDownload"

The bubble is misaligned since the media controls move after it starts playing.
Also the bubble doesn't realign or dismiss on orientation change.

Once we have the right coordinates of the download button, we can add a pulse drawable.

Deleted: xyz.mp4 5.7 MB

	xyz.mp4 5.7 MB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fcfd6880c1e15dae6e2870aa2f7307123d48f136

commit fcfd6880c1e15dae6e2870aa2f7307123d48f136
Author: Shakti Sahu <shaktisahu@chromium.org>
Date: Thu Oct 05 03:55:34 2017

In-product-help : Various fixes for media download button IPH

1 - This CL tries to fix the coordinates where the media download IPH bubble
should be shown. Currently we show it as soon as it starts playing, but
the controls moves down afterwards and we should probably set it after
it has settled.

2 - Added a y-offset to account for the viewport location offset on screen.

3 - Dismiss the in-product-help message after a orientation change.
This should be unnecessary if blink could send us the correct coordinates
after the rotate.

4 - Added a pulse highlight around the download button.

Bug:  761085 
Change-Id: Id21c67f65f077ac69fd2d8c862433f1e476085d8
Reviewed-on: https://chromium-review.googlesource.com/661051
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506636}
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/chrome/android/java/src/org/chromium/chrome/browser/widget/textbubble/TextBubble.java
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/chrome/browser/android/tab_android.cc
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/third_party/WebKit/Source/modules/media_controls/MediaControlsImplTest.cpp
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/third_party/WebKit/Source/modules/media_controls/MediaDownloadInProductHelpManager.cpp
[modify] https://crrev.com/fcfd6880c1e15dae6e2870aa2f7307123d48f136/third_party/WebKit/Source/modules/media_controls/MediaDownloadInProductHelpManager.h