This PR modifies the existing API docs samples to use DartPad so that all of the samples are now interactive apps on the API docs site.
It also removes the restriction for the max width of the description area so that the dartpad region can expand horizontally.
I updated the first paragraph on the API docs to indicate that Flutter is more than just mobile now (same text as the README.md at the top level).
I modified a few of the examples so that they looked nicer, and fit better on the page.
I added the sample description text above each DartPad instance, since that often defines the context of the example.
I removed animations and images when they were redundant with the sample content. There were a few that made sense to keep, so I did.
* c9322145f Ensure fields of Rect and OffsetBase classes are optimized as non-null. (flutter/engine#16465)
* 5c70356a9 Simplify task queues locking mechanism (flutter/engine#16477)
* d589ddea6 Fix text range logic for a11y (flutter/engine#16496)
* 1a4f4e394 Fix unused import in Android embedder (flutter/engine#16494)
* 964ae1009 Disable ShellTest.WaitForFirstFrameTimeout on Fuchsia (flutter/engine#16495)
* 6158f03ef Roll src/third_party/skia 87e3bef6f82f..9f3eef796f63 (7 commits) (flutter/engine#16493)
The current implementation of DropdownButtonFormField does not pass the initial value to _DropdownButtonFormFieldState. As a result changes made through the child DropdownButton are not made to the FormFieldState and the widget is not updated unless a onChanged function is provided to the DropdownButtomFormField constructor.
This change modifies DropdownButtonFormField to behave more consistently with other FormField widgets in how the Form state is handled.
* d5442b86e Roll src/third_party/skia bc3307c395e2..ebc00f97fab1 (21 commits) (flutter/engine#16429)
* 76b291a65 Added a plugin method that gets called when the engine is about to be deleted (flutter/engine#16336)
* 07f25c51e fix bad reference to maxDiffRatePercent (flutter/engine#16440)
* 41d50c220 Reland #16206: "[web] Correct getPositionForOffset for multi-line paragraphs" (flutter/engine#16365)
* f25d325b1 [fuchsia] change kMaxFramesInFlight to 3 (flutter/engine#16425)
* 473f55940 Suppress some deprecation warnings on Windows (flutter/engine#16416)
* 2e34ad6b7 Roll fuchsia/sdk/core/mac-amd64 from ubThi... to fvWgE... (flutter/engine#16454)
* 47c02e6fc Roll src/third_party/skia ebc00f97fab1..cbf79b95c2d4 (4 commits) (flutter/engine#16456)
* 3d1b112d7 Roll buildroot (flutter/engine#16419)
* 28e663726 Add explicit casts to printing of function pointers (flutter/engine#16370)
* 9ad81dae1 Wrap strdup to use compliant name on Windows (flutter/engine#16372)
* 9708e5274 Roll rapidjson (flutter/engine#16347)
* f06ebba3e Include <memory> in hb_wrapper.h because unique_ptr is used. (flutter/engine#16442)
* e530376fb Roll fuchsia/sdk/core/linux-amd64 from VJv0H... to A9STP... (flutter/engine#16457)
* 4cc41ae97 Roll src/third_party/skia cbf79b95c2d4..4721e067812f (1 commits) (flutter/engine#16459)
* 2f233edf5 Roll src/third_party/skia 4721e067812f..f6e3eaf05150 (1 commits) (flutter/engine#16461)
* b0b0ed83b Roll src/third_party/skia f6e3eaf05150..cc21d0c1f2ce (1 commits) (flutter/engine#16463)
* 7fea936a0 Roll src/third_party/skia cc21d0c1f2ce..116b33e8ab21 (3 commits) (flutter/engine#16466)
* 001b3a0b1 Roll src/third_party/skia 116b33e8ab21..7f36405ea3ec (3 commits) (flutter/engine#16471)
* f3ce90e93 Reset width/height before deallocation for Safari allocation bug. (flutter/engine#16469)
* 9347c93fc Roll src/third_party/dart c8ed304e979a..3414b5167554 (52 commits) (flutter/engine#16362)
* 16cd6f093 Roll fuchsia/sdk/core/mac-amd64 from 6h3IH... to Ke00Y... (flutter/engine#16360)
* 8c6cc65cd Fix runtime type errors when running with canvaskit (flutter/engine#16312)
* 677b563b9 Refactor of Vulkan GPUSurface code (flutter/engine#16224)
* 7ca44d339 Kill the test harness if any test exceeds a timeout. (flutter/engine#16349)
* 7f6149cbd Revert "Remove use of the deprecated AccessibilityNodeInfo boundsInPa… (flutter/engine#16355)
* 488f489bc Roll fuchsia/sdk/core/linux-amd64 from Tszo5... to VJv0H... (flutter/engine#16363)
* 7c9b11a80 Roll src/third_party/skia 71ce449d2814..2aee7d24da8f (5 commits) (flutter/engine#16364)
* 7e1d1440a Expose enable-service-port-fallback switch (flutter/engine#16366)
* 4cda916d5 Expose the dart kernel snapshot target and copied assets as a public dependency (flutter/engine#16266)
* 73c513041 Roll src/third_party/dart 3414b5167554..68e904e444dc (17 commits) (flutter/engine#16367)
* 1cd8f3b1a Fix and consolidate wstring conversion utils (flutter/engine#16342)
* b98a39e0b Add docs (flutter/engine#16368)
* e3e6de2ae Roll buildroot to c44791c89d2b51bfce864ab2cf5228d41ece1fcc (flutter/engine#16371)
* e24ec598e Fuchsia a11y actions (flutter/engine#16321)
* d8400c9cc Roll src/third_party/skia 2aee7d24da8f..14d64afaa8a3 (10 commits) (flutter/engine#16374)
* eeabd4d86 Roll src/third_party/dart 68e904e444dc..48808f7dce81 (17 commits) (flutter/engine#16377)
* 22b994c9c Roll fuchsia/sdk/core/mac-amd64 from Ke00Y... to ubThi... (flutter/engine#16378)
* 0471f44e9 Roll src/third_party/skia 14d64afaa8a3..6c9b1fd6663e (7 commits) (flutter/engine#16380)
* 852d8244c Roll src/third_party/dart 48808f7dce81..34893faa6079 (7 commits) (flutter/engine#16381)
* 4aa2083cf Roll src/third_party/skia 6c9b1fd6663e..bc3307c395e2 (1 commits) (flutter/engine#16383)
* 036c370c3 Copied Apple's semantics for switches, made checkboxes the same. (flutter/engine#16211)
* c107969ec fix build_id logic for fuchsia symbols (flutter/engine#16397)
* 11b770489 [fuchsia] Migrate flutter runner to use Present2 (flutter/engine#14162)
* 646ec3544 Update license output (flutter/engine#16379)
* 925c60b38 Fix Windows embedding issues caught by clang (flutter/engine#16369)
* 31bf3e110 Roll src/third_party/dart 34893faa6079..b3396cbdcae1 (36 commits) (flutter/engine#16422)
* 8f89bac4b [web] Fixes incorrect transform when context save and transforms are deferred. (flutter/engine#16412)
* f34bc65be use percent for golden diff rates; tighten the values (flutter/engine#16430)
