EXO: Change FullscreenShellSurface to correctly set widget bounds

Set params.bounds for widget within FullscreenShellSurface

Bug: 896710
Test: FullscreenShellSurfaceTest.Bounds
Change-Id: I250e99c177a2fd4ad15fab64d5a7929195441cb6
Reviewed-on: https://chromium-review.googlesource.com/c/1336000
Commit-Queue: Shawn Gallea <sagallea@google.com>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608793}
2 files changed