fix(chromium): preserve binary response body with text content-type

[SebTardif]

Summary

• Detect binary body corruption from CDP's UTF-8 decoding by comparing Content-Length with decoded buffer length
• Fall through to loadNetworkResource + IO.read stream path which preserves binary fidelity

When a server responds with Content-Type: text/plain;charset=UTF-8 but the body is binary, CDP's Network.getResponseBody decodes it as UTF-8 (base64Encoded: false), replacing invalid byte sequences with U+FFFD. For example, 8 bytes [0x80, 0x81, 0x82, 0xFF, 0xFE, 0x00, 0x01, 0x02] become 18 bytes after each invalid byte is replaced with a 3-byte replacement character.

The workaround detects this by comparing Content-Length with the decoded buffer's byte length. On mismatch, it re-fetches from cache via Network.loadNetworkResource, which returns raw bytes through IO.read streams without UTF-8 interpretation.

Chromium-only fix. WebKit has the same CDP-level behavior but no loadNetworkResource equivalent. Firefox is unaffected (always returns base64).

Prior art

• #14941: The loadNetworkResource fallback path was originally added for prefetch scripts that return empty bodies. This PR extends the same mechanism to handle binary body corruption.

Fixes #40510

[yury-s]

Would be better if we fixed on the browser end. @Skn0tt what's your take on that?

[github-actions]

Test results for "MCP"

10 failed
❌ [chrome] › mcp/annotate.spec.ts:57 › should capture multiple screenshots in one annotation @mcp-windows-latest-chrome
❌ [chrome] › mcp/annotate.spec.ts:110 › should abort annotation when last screenshot is removed @mcp-windows-latest-chrome
❌ [chrome] › mcp/annotate.spec.ts:137 › should abort MCP annotation when last screenshot is removed @mcp-windows-latest-chrome
❌ [msedge] › mcp/annotate.spec.ts:137 › should abort MCP annotation when last screenshot is removed @mcp-windows-latest-msedge
❌ [msedge] › mcp/annotate.spec.ts:251 › should start dashboard and annotate when no dashboard is running @mcp-windows-latest-msedge
❌ [msedge] › mcp/annotate.spec.ts:273 › should enter annotate mode on fresh dashboard.tsx mount with -s --annotate @mcp-windows-latest-msedge
❌ [msedge] › mcp/annotate.spec.ts:297 › should annotate via direct browser_annotate MCP call @mcp-windows-latest-msedge
❌ [msedge] › mcp/annotate.spec.ts:330 › should annotate when context has no fixed viewport @mcp-windows-latest-msedge
❌ [msedge] › mcp/annotate.spec.ts:367 › should cancel browser_annotate when the MCP request is aborted @mcp-windows-latest-msedge
❌ [msedge] › mcp/annotate.spec.ts:476 › should disengage annotate mode when --annotate client disconnects @mcp-windows-latest-msedge

1 flaky

⚠️ [msedge] › mcp/cdp.spec.ts:24 › cdp server `@mcp-windows-latest-msedge`

7059 passed, 1068 skipped

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Merge workflow run.

[github-actions]

Test results for "tests 1"

11 failed
❌ [chromium-page] › page/page-goto.spec.ts:747 › should report raw buffer for main resource @ubuntu-22.04-chromium-tip-of-tree
❌ [chromium-page] › page/page-request-fulfill.spec.ts:445 › should fulfill with gzip and readback @ubuntu-22.04-chromium-tip-of-tree
❌ [chromium-page] › page/page-goto.spec.ts:747 › should report raw buffer for main resource @chromium-ubuntu-22.04-arm-node20
❌ [chromium-page] › page/page-request-fulfill.spec.ts:445 › should fulfill with gzip and readback @chromium-ubuntu-22.04-arm-node20
❌ [chromium-page] › page/page-goto.spec.ts:747 › should report raw buffer for main resource @chromium-ubuntu-22.04-node24
❌ [chromium-page] › page/page-request-fulfill.spec.ts:445 › should fulfill with gzip and readback @chromium-ubuntu-22.04-node24
❌ [chromium-page] › page/page-goto.spec.ts:747 › should report raw buffer for main resource @chromium-ubuntu-22.04-node20
❌ [chromium-page] › page/page-request-fulfill.spec.ts:445 › should fulfill with gzip and readback @chromium-ubuntu-22.04-node20
❌ [chromium-page] › page/page-goto.spec.ts:747 › should report raw buffer for main resource @chromium-ubuntu-22.04-node22
❌ [chromium-page] › page/page-request-fulfill.spec.ts:445 › should fulfill with gzip and readback @chromium-ubuntu-22.04-node22
❌ [webkit-page] › page/page-network-response.spec.ts:152 › should return binary body with text content-type @webkit-ubuntu-22.04-node20

3 flaky

⚠️ [installation tests] › playwright-test-package-managers.spec.ts:19 › npm: @playwright/test should work `@package-installations-windows-latest`
⚠️ [chromium-library] › library/popup.spec.ts:261 › should not throw when click closes popup `@ubuntu-22.04-chromium-tip-of-tree`
⚠️ [chromium-library] › library/video.spec.ts:719 › screencast › should work with video+trace `@chromium-ubuntu-22.04-node22`

41753 passed, 850 skipped

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Merge workflow run.