Updated the libwebp with version 0.4.0-rc1

Updated the libwebp with the release 0.4.0-rc1 (change#I22be12d8).

Build & Ran following tests for Nexus N7 (Razor)
runtest --path cts/tests/tests/graphics/src/android/graphics/cts/BitmapTest.java
runtest --path cts/tests/tests/graphics/src/android/graphics/cts/BitmapFactoryTest.java
runtest --path cts/tests/tests/graphics/src/android/graphics/cts/BitmapRegionDecoderTest.java
runtest --path cts/tests/tests/graphics/src/android/graphics/cts/Bitmap_CompressFormatTest.java
runtest --path cts/tests/tests/graphics/src/android/graphics/cts/Bitmap_ConfigTest.java
runtest --path cts/tests/tests/graphics/src/android/graphics/cts/BitmapFactory_OptionsTest.java
runtest --path cts/tests/tests/graphics/src/android/graphics/cts/BitmapShaderTest.java

Also did the full Android build for following targets:
- flo
- grouper
- mako
- x86

Before this change is submitted, need to submit the change for cts/tests to update the threshold for WebP encoding for color-mode RGB565.
(Refer: https://googleplex-android-review.git.corp.google.com/#/c/403360/)

Change-Id: Ib2db2ebf0395276d45c3e8dc70d7b451e3678e6f
Fix WebP decode bug for ARGB_4444 color-mode.

Fix the bug for decoding in rgbA_4444 & RGBA_4444 color-modes.
The WEBP_SWAP_16BIT_CSP flag needs to be honored while filling the
Alpha (4 bits) data in the destination buffer and while pre-multiplying
the alpha to RGB colors.

Change-Id: I4468a996fbe6cbb5f41c6300d226606e4c224e06
NDK build support for libwebp-decode library

Change-Id: Id5ae945979343603919bbb3acca921f3392f9e25
libwebp modules should depend on their makefile

This is to make sure that any change to the makefile triggers rebuilding
of the module.

Change-Id: Iddbdb034d42fd943e83c610ceb25628c21d43e9d
libwebp modules should depend on their makefile

This is to make sure that any change to the makefile triggers rebuilding
of the module.

(cherry picked from commit d68e528902de4473052751486098fc10737338cf)

Change-Id: I1cde729bba94c3d507f308f5131bb50f260e1277
Merge "libwebp modules should depend on their makefile"
am 0db01fc3: Merge "libwebp modules should depend on their makefile"

* commit '0db01fc3411621bec473d50db0071fd2a225962e':
  libwebp modules should depend on their makefile
external/webp: cherry-pick upstream alpha decode bugfix

fix out-of-bound read during alpha-plane decoding

From upstream: https://gerrit.chromium.org/gerrit/#/c/69363/

Change-Id: I38ba2773f41a2c028b3fbf9eef303b64958c5f12
Move module definitions to parent dir

Previously "../"s in LOCAL_SRC_FILES lead to object files out
of the module's intermediate dir and caused build race condition.

Change-Id: I3c3fc05feaf144d4223b8ca5b86a2c497078d2ba
Cherry-pick upstream bugfix for incremental decode of lossy-alpha

When remapping buffer, br->eos_ was wrongly being set to true for
certain images.

From upstream: https://gerrit.chromium.org/gerrit/#/c/69849/

Change-Id: I933f2da8a6d1c497f8e54ae6fb5bcfc0171660df
Sync-patch with libwebp ver 0.4.1

Sync-patch with libwebp ver 0.4.1-rc1 (change#I5346984d2).
  - NEON assembly optimizations:
    - ~25% faster lossy decode / encode (-m 4)
    - ~10% faster lossless decode
    - ~5-10% faster lossless encode (-m 3/4)
  - Arch64 (arm64) & MIPS support/optimizations.
The bug for this request is b/16624377

Ran (OK/Pass) following cts tests for N7 (Razor/flo) & N8 (Volantis/flounder).

cts-tradefed run cts -d -c android.graphics.cts.BitmapTest
cts-tradefed run cts -d -c android.graphics.cts.BitmapFactoryTest
cts-tradefed run cts -d -c android.graphics.cts.BitmapRegionDecoderTest
cts-tradefed run cts -d -c android.graphics.cts.Bitmap_CompressFormatTest
cts-tradefed run cts -d -c android.graphics.cts.Bitmap_ConfigTest
cts-tradefed run cts -d -c android.graphics.cts.BitmapFactory_OptionsTest
cts-tradefed run cts -d -c android.graphics.cts.BitmapShaderTest

Change-Id: Idf2756b8881d10001c0663bca454aac86ab30a39