[M123]Ensure we check readability for all URLs.

This change adds readability checks for redirects and onLoadStarted calls. Additionally, I added some per-entrypoint histograms tracking playback successes and failures and how often do we trigger playbacks without readability checks. I think some UI races are still possible, so this is most likely not the final fix, but definitely a step in the right direction

Bug: b/327453119
Bug: 328271376

(cherry picked from commit 99a85789670c89dfe9eeabbe71ad4008e4e81db0)

Change-Id: I43fe30f865a6230d137e2d89d785e25631627eaf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5341662
Reviewed-by: Ian Wells <iwells@chromium.org>
Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Commit-Queue: Basia Zimirska <basiaz@google.com>
Cr-Original-Commit-Position: refs/heads/main@{#1268687}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5356614
Auto-Submit: Basia Zimirska <basiaz@google.com>
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/branch-heads/6312@{#558}
Cr-Branched-From: 6711dcdae48edaf98cbc6964f90fac85b7d9986e-refs/heads/main@{#1262506}

• chrome/android/java/src/org/chromium/chrome/browser/app/ChromeActivity.java[diff]
• chrome/android/junit/src/org/chromium/chrome/browser/ChromeActivityUnitTest.java[diff]
• chrome/browser/readaloud/android/java/src/org/chromium/chrome/browser/readaloud/ReadAloudController.java[diff]
• chrome/browser/readaloud/android/java/src/org/chromium/chrome/browser/readaloud/ReadAloudControllerUnitTest.java[diff]
• chrome/browser/readaloud/android/java/src/org/chromium/chrome/browser/readaloud/ReadAloudMetrics.java[diff]
• chrome/browser/readaloud/android/java/src/org/chromium/chrome/browser/readaloud/ReadAloudToolbarButtonController.java[diff]
• tools/metrics/histograms/metadata/readaloud/enums.xml[diff]
• tools/metrics/histograms/metadata/readaloud/histograms.xml[diff]