- Replaced 'Building, Running, and Debugging' section
  - Previously, this section was incomplete and only described how to
build chromium.
  - Added instructions to run and visually debug as well.
  - Updated build instructions to support debugging.
- Simplified recommended CMakeLists.txt file
- Simplified instructions for creating a desktop entry
- Increased recommended VM option Xmx from 5g to 10g
- Marked optional steps as optional
- Punctuation fixes
- Added link to clion.md to docs/README.md

Change-Id: Id0514b1498517e0c10fafb1a9639aeda44717921
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1976280
Commit-Queue: manuk hovanesian <manukh@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#726546}