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This is a purely refactoring CL. We are adding support for regex rules to DNR.
Currently RulesetMatcher is tasked with evaluating a single ruleset source (An
extension can have upto two ruleset sources: static and dynamic). RulesetMatcher
implements matching of filter list style rules supported by url_pattern_index.

This CL does the following:
- Introduce an interface called RulesetMatcherInterface.
- Introduce ExtensionUrlPatternIndexMatcher: this will handle all filter list
  style rules within a ruleset.
- Move most of the implementation from RulesetMatcher to
  ExtensionUrlPatternIndexMatcher. After this CL RulesetMatcher is just a
  wrapper over ExtensionUrlPatternIndexMatcher.
- A subsequent CL will
   - Introduce RegexRulesMatcher which will handle all regex rules within a
     ruleset. It will also implement the RulesetMatcherInterface.
   - RulesetMatcher owns a ExtensionUrlPatternIndexMatcher currently.
     Subsequently it will also own a RegexRulesMatcher and combine the results
     from the two.

BUG=974391
Doc=https://docs.google.com/document/d/1mRErUMII_gSSPaHmxyn31UOYWUaZLj0xOaezekxD2-Y/edit?usp=sharing (Internal)

Change-Id: I580be59c8b19840622c2c673338c0f54087f5186
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879565Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710611}