Delete `//chrome/services/qrcode_generator`.

After go/rusty-qr-code-generator we no longer need a separate service
that delegates QR code generation to a separate process.  Therefore this
CL deletes the `//chrome/services/qrcode_generator` directory.

* `qr_code_generator_pixeltest.cc` has been moved to
  `//chrome/browser/sharing` (as I am not sure if pixel tests are
  supported for `components_browsertests` - this has been discussed in
  https://crrev.com/c/5278872/8#message-5b43795fe4019875ebb87e19e95b49e08947133b).
* Code that draws a QR code into a `SkBitmap` has been moved from
  `//chrome/services/qrcode_generator/qrcode_generator_service_impl.*`
  to `//components/qr_code_generator/bitmap_generator.*`.
* `qrcode_generator.mojom` has been deleted:
    * Bitmap style enums (e.g. `LocatorStyle`) have been moved into
      `//components/qr_code_generator/bitmap_generator.h`
    * Error codes have been moved into
      `//components/qr_code_generator/qr_code_generator.h`
    * Fields of `GenerateQRCodeRequest` have been "splat" into
      parameters of the new `GenerateBitmap` function
    * `GenerateQRCodeResponse` has been replaced with a new
      `QRImage` struct plus `base::expected<QRImage, Error>`
* `QRImageGenerator` class has been deleted and its method
  has been refectored:
    * The method became a free function
    * The result is now returned directly instead of via a callback

This CL is quite big - I appologize.  Splitting this CL into smaller
pieces is a bit difficult, mostly because it seems hard to defining some
types in `.mojom` and some in `.h`.

Bug: 40263739
Change-Id: I39db6f56ad4138d8169e64fc715c10adfc32ca0d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5278872
Reviewed-by: Gavin Williams <[email protected]>
Reviewed-by: Peter Williamson <[email protected]>
Reviewed-by: Adam Langley <[email protected]>
Reviewed-by: danakj <[email protected]>
Reviewed-by: Kyle Horimoto <[email protected]>
Commit-Queue: Ɓukasz Anforowicz <[email protected]>
Reviewed-by: Ken Buchanan <[email protected]>
Reviewed-by: Mitsuru Oshima <[email protected]>
Owners-Override: danakj <[email protected]>
Reviewed-by: Robert Phillips <[email protected]>
Reviewed-by: Colin Blundell <[email protected]>
Reviewed-by: Ryan Hansberry <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1261280}
diff --git a/docs/security/faq.md b/docs/security/faq.md
index fd4c56b2..10b6e14c 100644
--- a/docs/security/faq.md
+++ b/docs/security/faq.md
@@ -372,8 +372,8 @@
 No. Denial of Service (DoS) issues are treated as **abuse** or **stability**
 issues rather than security vulnerabilities.
 
-*    If you find a reproducible crash, we encourage you to [report
-     it](https://issues.chromium.org/new).
+*    If you find a reproducible crash (e.g. a way to hit a `CHECK`),
+     we encourage you to [report it](https://issues.chromium.org/new).
 *    If you find a site that is abusing the user experience (e.g. preventing you
      from leaving a site), we encourage you to [report
      it](https://issues.chromium.org/new).