[M123] Read Aloud Tap To Seek

Adds tap to seek for Read Aloud behind a flag.

Uses Boyer Moore to find the string returned by Contextual Search in the distilled Read Aloud text. If a match is found, playback seeks to that point.

TODO: b/325308883 to hide Tap to Search UI when playback is active.

(cherry picked from commit 74eea4e1c9d6bd12d0a1d1a1ffa461ecf2f8e88d)

Bug: 305737581, b/326975726
Change-Id: Ic24eb1d786836def9ce919d81209e0ab5a7134f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5287843
Reviewed-by: Basia Zimirska <basiaz@google.com>
Commit-Queue: Andrea Gomez <andreaxg@google.com>
Reviewed-by: Gang Wu <gangwu@chromium.org>
Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1268181}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5350702
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/branch-heads/6312@{#460}
Cr-Branched-From: 6711dcdae48edaf98cbc6964f90fac85b7d9986e-refs/heads/main@{#1262506}

• chrome/android/chrome_java_sources.gni[diff]
• chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java[diff]
• chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchSelection.java[Added - diff]
• chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchSelectionObserver.java[Added - diff]
• chrome/android/java/src/org/chromium/chrome/browser/ui/RootUiCoordinator.java[diff]
• chrome/browser/flags/android/chrome_feature_list.cc[diff]
• chrome/browser/flags/android/chrome_feature_list.h[diff]
• chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureList.java[diff]
• chrome/browser/readaloud/android/BUILD.gn[diff]
• chrome/browser/readaloud/android/java/src/org/chromium/chrome/browser/readaloud/BoyerMoore.java[Added - 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/ReadAloudFeatures.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/TapToSeekHandler.java[Added - diff]
• chrome/browser/readaloud/android/java/src/org/chromium/chrome/browser/readaloud/TapToSeekHandlerUnitTest.java[Added - diff]
• tools/metrics/histograms/metadata/readaloud/histograms.xml[diff]